Change by default: Exploring the effects of a sudden influx of newcomers on the discourse of r/TwoXChromosomes
First Monday

Change by default: Exploring the effects of a sudden influx of newcomers on the discourse of r/TwoXChromosomes by Elliot Panek, Wyatt Harrison, and Jue Hou

Sudden influxes of new contributors to online communities can cause apprehension and resentment among existing members, potentially leading to the displacement of existing members by newcomers. We analyze the impact of a sudden influx of new contributors to r/TwoXChromosomes, an online community in which the experiences and perspectives of female-identified individuals are discussed. Though we find evidence of a small displacement effect, other factors, such as the passage of time and the 2016 U.S. presidential election, have far larger impacts on the retention of existing contributors. We also find that after the influx, discussion topics shifted temporarily toward general statements about women and men, followed by a lasting shift away from appearance-related topics toward topics relating to motherhood. In sum, the evidence suggests that in this particular case, fears of displacement by a sudden influx of newcomers are exaggerated, and that technology designers, users, and online community managers should consider the impact of a wider variety of factors when considering how to maintain cohesive online communities.






Over the past decade, anonymous, topic-oriented discussion communities have enjoyed significant growth. Nowhere is this growth more evident than among the topic-oriented discussions hosted on Reddit, a Web site and mobile application that allows registered users to create topic-oriented discussion groups (i.e., ‘subreddits’), engage in discussions, and vote on content and comments to increase or decrease their subsequent visibility. Since 2008, Reddit has grown from several hundred subreddits with a cumulative total of several hundred thousand comments posted per month to over one million subreddits with, cumulatively, over 100 million comments posted per month (, 2018).

In addition to growth in the number of subreddits, many individual subreddits have grown significantly in terms of the number of contributors to discussions. This ‘community-level’ growth can be framed in positive ways: as democratization of a medium formerly reserved for a privileged few, or as necessary for survival in competitive marketplaces of attention. However, many contributors to online communities view growth with a degree of apprehension (Grossman, 1997), characterizing newcomers as unwelcome outsiders or interlopers (Buyukozturk, et al., 2018). Chief among the fears of long-time contributors is the fear that new contributors will displace existing contributors. Even in online spaces that do not have limitations that constrain the number of members of communities, displacement can result from growth. One potential process by which such displacement occurs relates to interests and perspectives of the community evident in comments posted by users. As new members contribute to discourse, the topics and/or tenor of discussions change in such a way that existing members no longer feel that participation is worthwhile. Though there is evidence that long-time contributors to online discourse view new contributors as a potential threat to the integrity of online communities (Boero and Pascoe, 2012; Honeycutt, 2005; Yeshua-Katz, 2016), researchers have yet to use large-scale quantitative analyses to examine the phenomenon of displacement as it relates to changing patterns of participation and qualities of expressions in an online community.

The present study explores this phenomenon through an analysis of growth, commenter displacement, and the topics of discourse in TwoXChromosomes, a subreddit dedicated to discussions ‘relevant to the existence and/or experience of girlhood, from any perspective’ (TwoXChromosomes, 2018). TwoXChromosomes (2XC) is an ideal community in which to study interrelations of growth, contributor displacement, and topics of discourse because of how the size of the community (i.e., the number of commenters) varied over the course of its nine-year history. After three years of steady growth and two years of stagnation, 2XC experienced a sudden influx of commenters in May of 2014, trebling in size overnight. This sudden growth was largely the result of the website adding the subreddit to the list of ‘default’ subreddits that are seen by all new users. By examining whether or not commenters who contributed to 2XC’s discourse prior to May 2014 remained after this event, we provide evidence that speaks to the questions of whether sudden growth necessarily comes at the expense of existing community members, and how sudden growth affects qualities of discussions. Additionally, we contribute to the study of all online communities by introducing a novel means of analyzing online community growth.

Situating TwoXChromosomes within the context of Reddit

Before proceeding, it is necessary to describe several attributes of Reddit that are relevant to questions of community growth and its effects on discourse. In contrast to other popular social media platforms such as Facebook, Reddit does not foreground users’ identities or levels of experience or expertise. Though the site has made recent efforts to add functionality similar to social networking websites such as the ability to follow another user’s posts and comments, Reddit has more closely resembled a collection of discussion boards for most of its history. As such, Reddit is less of a way to connect to other individuals and more a way to distribute and access content and a venue for discussions.

Subreddits are public by default, meaning that any registered user can contribute content or comments. Newcomers need not petition a moderator in order to contribute, nor do they need to join, follow, or subscribe to a subreddit to post or comment. The size of subreddits such as 2XC (which, prior to the time it was added to the default subreddits in May 2014, possessed 8,506 unique contributors per month) and the difficulty of determining a user’s prior contributions make the process of ‘gatekeeping’ — preventing certain types of newcomers from joining discourse — more difficult than is the case in many smaller online and off-line communities. Whereas existing users of many online communities present newcomers with a variety of barriers or boundaries to gaining acceptance (Gallagher and Savage, 2015; Yeshua-Katz, 2016), Reddit’s relative openness and increasing popularity make such ‘boundary work’ difficult.

The visibility of posts and comments on Reddit is determined by other registered users, who may ‘upvote’ or ‘downvote’ each post or comment. Content and comments are typically sorted by the number of upvotes minus the number of downvotes received. This sorting mechanism has the effect of flattening Reddit’s hierarchy [1] — experienced users’ votes are worth no more than those of newcomers — while providing another means by which large influxes of newcomers can change discussions. In addition to simply contributing comments to discussions, newcomers may upvote comments that reflect their preferences and sensibilities. Commenters who receive fewer upvotes are less likely to have their comments seen by other users, and may feel less motivated to contribute in the future (Halavais, 2009). It is thus through their voting power that large groups of newcomers may affect subsequent discourse in subreddits such as 2XC.

Just as it is relatively easy to contribute to any given subreddit, it is relatively easy to start new subreddits. There are no special qualifications one must possess in order to create a subreddit, though attracting and retaining enough users to regularly contribute the engaging content or commentary necessary to sustain subreddits is difficult. In the cases of 2XC and other subreddits that experienced sudden influxes of newcomers and/or changes to moderation rules, long-time contributors have created ‘splinter subreddits’ (e.g., r/TrollXChromosomes) that respond to a perceived demand for content and comments reflecting the interests of users prior to the change in contributorships or rules. Such splinter subreddits may allow existing contributors to retain access to the types of content and discussions to which they’ve become accustomed even after abandoning the original subreddit, decreasing the cost of leaving and increasing the likelihood of displacement.

Having established the relative ease with which contributors may enter and leave the online discussion communities of Reddit, we now briefly survey extant research on the reactions of existing contributors to sudden influxes of newcomers to online discourse.

Eternal Septembers

Sudden influxes of new contributors to online communities are not uncommon. Usenet, one of the first collections of open online discussion-based communities, experienced such influxes every September, when college students who could not otherwise access the Internet would join the group in large numbers. In 1993, the popular Internet service provider America Online provided its users with access to Usenet, resulting in a significantly larger influx of new contributors. Many new contributors, including users who posted frequent business solicitations (i.e., ‘spam’), stayed, leading some users to refer to the influx as an ‘Eternal September’ (Grossman, 1997). Long-time members of the Usenet communities lamented the influx, observing that the new contributors had changed the character of the community via their contributions to the discussions (Grossman, 1997; Kiene, et al., 2016).

Since then, many online communities have recognized the disruptive power of a sudden influx of newcomers and dealt with its consequences. Newcomers can disrupt experienced users’ sense of the continuity of online communities, either due to newcomers’ earnest unfamiliarity with community norms or as a result of newcomers’ deliberate attempts to disrupt or change those norms (Kraut, et al., 2012). There is also the sense, among many experienced members of online communities, that newcomers lack the level of commitment required to continually post the substantive contributions that are online communities’ lifeblood (Kraut, et al., 2012). These beliefs about the influence of newcomers have been borne out in several empirical studies. In the context of Wikipedia, a collectively created knowledge repository, newcomers were found to be more likely to vandalize pages (Adler and Alfaro, 2007). Massa’s (2017) study of Anonymous, a diffuse online community which migrated across a variety of message boards and platforms for over a decade, demonstrated a link between a rapid influx of new visitors and a shift away from conversations about free speech toward other activism-related topics (e.g., human rights) [2].

Specific attributes of Reddit have precipitated sudden influxes of newcomers to various subreddits. New Reddit users are shown content from a collection of subreddits. Once registered, users have the ability to curate the subreddits that appear on their home page. The subreddits that comprise the uncurated lists of content are known as ‘default’ subreddits. The default subreddit are a kind of entry point for new users; the list of default subreddits have been changed by Web site administrators periodically ( before being phased out in 2017 (Social Media Week, 2017). When a subreddit was added to the list of defaults, its exposure to new Reddit users increased and the number of contributors to its discourse typically increased as well (Lin, et al., 2017).

The impact of contributions of newcomers on an online community can be assessed in a variety of ways. Previous studies have used grounded theory, in-depth interviews, and ethnographic methods to assess community members’ subjective experiences of such changes (e.g., Kiene, et al., 2016; Massanari, 2014; Rivera and Cox, 2016). Relevant to the focus of the current study, Lin and colleagues (2017) examined three outcomes relating to sudden influxes of newcomers to 10 subreddits: existing users’ subjective responses to new content (manifest by complaint comments in response to newcomers’ comments); the topic specificity of content of comments (i.e., specifically, whether or not the topics of comments posted by newcomers tended to be less distinct from the topics posted on Reddit generally); the tendency of newcomers to comment on a smaller proportion of content. Most relevant to the research questions addressed in the present study, they did not find evidence that sudden influxes of new commenters caused discussion topics to change in relation to the topics generally addressed on Reddit at large.

In this study, we build on this existing body of research on the impact of newcomers to online topic-oriented discussion communities by examining two facets of change. Additionally, we are interested in the extent to which changes, should they exist, are temporary or lasting. By taking a wide view of the community and examining nearly a decade of discourse on 2XC, we speak to these questions directly. Our research questions, stated below, are intended to address the concerns of community members and to take into account both the collective makeup of contributors to discourse (who is speaking) and the content of discourse (what is being said):

RQ1a: Did the sudden influx of newcomers to 2XC in May 2014 displace existing contributors?
RQ1b: If a displacement effect occurred, did it last?
RQ2a: In what ways, if any, did the topics of discussions change in response to the addition of 2XC to the defaults?
RQ2b: If a change occurred, did the prevalence of particular topics persist over time?





For the purposes of this study, we accessed a publicly accessible database containing all comments posted on Reddit from 2005 to 2018 (, 2018). We used SQL and Python code to assess the variables outlined in the following sub-sections. The database structure allows us to determine the usernames of contributors to 2XC for each month. It also allows us to sample comments made in 2XC each month. We examined usernames of contributors and comment samples from the first month of 2XC’s existence, July 2009, to July 2018. Thus, the sample included 58 months of data prior to the point in time at which 2XC was added to the default subreddits (May 2014), and 51 months including and after this point in time. The unit of analysis is one month.

Number of unique monthly commenters

To speak to the question of the degree to which the total number of contributors to 2XC’s discourse increased immediately after its addition to the default subreddits, the total number of unique commenters in each month from July 2009 to July 2018 was assessed through a database query (M = 14860.49; SD = 8803.18).

Commenter cohort retention and commenting frequency

To assess the balance of contributions during a given month from individuals who contributed prior to May 2014 (‘existing contributors’) and those who began contributing in or after May 2014 (‘newcomers’), we developed two novel means of assessing the levels of experience of commenters to 2XC in a given month. This was done chiefly to address the ways in which simply lumping all existing contributors together fails to reflect two key aspects of their status within the community: when they began contributing to discussions on 2XC (i.e., what commenter cohort they belonged to) and how frequently they contributed to discussions on 2XC (i.e., their commenting frequency). By taking into account the proportion of contributors in a given month from particular commenter cohorts and particular commenting frequency levels, we can create a more nuanced picture of the aggregate levels of experience among commenters in a given month. We developed a database query script that yielded the following information about each month of contributors of comments in 2XC: the number of contributors who had posted X number of previous months in 2XC (commenting frequency of contributors to 2XC for a given month) and the number of contributors from each prior commenter cohort.

Cohort retention rate

From month to month, each commenter cohort retains a percentage of its original size. For example, a cohort in which all commenters returned to comment in the subsequent month would have a retention rate of 100 percent, while a cohort in which half of the commenters returned to comment in the subsequent month would have a retention rate of 50 percent. In order to determine whether or not, or to what extent, existing contributors were displaced by newcomers, we must determine whether or not the retention rate of pre-May-2014 cohorts declined significantly immediately after May 2014. Retention rates were assessed by dividing the number of contributors from a given cohort during a given month by the original size of the cohort.


To account for the fact that cohorts may diminish in size over time, we created a variable that reflects the order in which a given month occurred in the history of the commenter cohort. By controlling for order, we can further isolate the unique contribution of the addition to the defaults on the cohort retention rates of pre-May-2014 cohorts.

Discussion topics

There are a variety of means by which to determine topics of discussions in online communities. Many content analyses of online discussion communities employ human coders (e.g., Gerstenfeld, et al., 2003), an approach which has the advantage of human understanding of context clues that may be absent from automated approaches. The disadvantage to this approach is that it renders the coding of large sets of content, such as the ones in the present study, impractical. Despite their limitations (e.g., inability to determine meaning in context to the extent that humans are capable), automated approaches to analyzing content can provide some basic insight into changing patterns within large sets of content (Lewis, et al., 2013).

Each month, hundreds of thousands of comments are posted to 2XC. So as to expedite the data analysis process, samples of 1,000 comments were downloaded for each month from July 2009 to July 2018 from the database. Comments were chosen by assigning all comments in the month a number, and then selecting numbers at random as a criterion for inclusion in the sample. These samples were then analyzed using Leximancer software. Leximancer uses a ‘semantic mapping’ method to evaluate the co-occurrence of particular words in a body of text. The program uses a kind of virtual space in which to locate words in relation to one another. Words that frequently co-occur are placed closer together while words that do not frequently co-occur are places further apart. This means of representing words in a virtual space (i.e., semantic mapping) mimics the manner in which humans learn language (Lin, et al., 1991; Smith and Humphreys, 2006). Words that cluster together are referred to as a ‘concept.’ Leximancer assigns a name to each concept based on the most frequently occurring word in the cluster.

Leximancer has no a priori knowledge of meaning or language. Thus, it was necessary for us to evaluate the list of concepts derived from the comment samples and determine which of these could be meaningfully understood as discussion topics. Some words (e.g., ‘control’, ‘things’) do not, in and of themselves, reveal much about meaning or context, either because they can be used to refer to a wide variety of ideas (e.g., ‘things’) are can be used in a variety of ways (e.g., to lose ‘control,’ or to use birth ‘control’). In analyzing each monthly set of comments, the program yields a list of concepts with coefficients that reflect the frequency with which the concepts occur in that set of comments. In the Appendix, we provide a list of all concepts derived from our complete set of 97 months of 1,000 comment samples, using bold type to denote concepts that were treated as discussion topics in our analysis.




Patterns in 2XC growth and commenter experience

Before addressing the question of 2XC commenter displacement in May 2014, it is important to establish the context in which such changes in commenter behavior were taking place. By examining changes over time to the overall number of 2XC commenters, commenter cohort size, cohort retention rates, and commenting frequency, we were able to establish a clear timeline of 2XC’s history (see Figures 1–8). This history was marked by periods of growth and decline, both gradual and sudden.


Overall number of commenters to r/TwoXChromosomes, July 2009-July 2018
Figure 1: Overall number of commenters to r/TwoXChromosomes, July 2009 — July 2018.
Note: Larger version of Figure 1 available here.



r/TwoXChromosomes July 2009 commenter cohort retention, July 2009-July 2018
Figure 2: r/TwoXChromosomes July 2009 commenter cohort retention, July 2009 — July 2018.
Note: Larger version of Figure 2 available here.



r/TwoXChromosomes Sept 2011 commenter cohort retention Sept 2011-July 2018
Figure 3: r/TwoXChromosomes Sept 2011 commenter cohort retention Sept 2011 — July 2018.
Note: Larger version of Figure 3 available here.



r/TwoXChromosomes Feb 2012 commenter cohort retention Feb 2012-July 2018
Figure 4: r/TwoXChromosomes Feb 2012 commenter cohort retention Feb 2012 — July 2018.
Note: Larger version of Figure 4 available here.



r/TwoXChromosomes May 2014 commenter cohort retention May 2014-July 2018
Figure 5: r/TwoXChromosomes May 2014 commenter cohort retention May 2014 — July 2018.
Note: Larger version of Figure 5 available here.



r/TwoXChromosomes contributors who commented in five separate months
Figure 6: r/TwoXChromosomes contributors who commented in five separate months.
Note: Larger version of Figure 6 available here.



r/TwoXChromosomes contributors who commented in 10 separate months
Figure 7: r/TwoXChromosomes contributors who commented in 10 separate months.
Note: Larger version of Figure 7 available here.



r/TwoXChromosomes contributors who commented in 20 separate months
Figure 8: r/TwoXChromosomes contributors who commented in 20 separate months.
Note: Larger version of Figure 8 available here.


The first period, from July 2009 to December 2011, shows steady growth: the overall number of commenters increases from month to month and a greater number of commenters of varying levels of commenting frequency — from those who had commented in only two different months to those who had commented in 10 different months — were being retained. Near the end of this period, from September 2011 to January 2012, we see evidence of commenter cohorts that are especially ‘loyal’: a greater proportion of cohorts who joined the 2XC discussions return to comment in subsequent months than the cohorts that preceded them or those that followed in the next two and a half years. Commenting frequency data corroborate this finding: 10 months subsequent to October 2011, we see a high point for commenters who had commented in 10 previous months; 20 months subsequent to October 2011, we see a high point for commenters who had commented in 20 prior months; 30 months subsequent to October 2011, we see a high point for commenters who had commented in 30 prior months. This suggests that during this period, 2XC is adding additional commenters and more of these commenters are continuing to contribute to discussions than was the case during any other period in the subreddit’s history.

Following this is a period of steady decline, from February 2012 to April 2014. The overall number of commenters declines, cohorts decrease in size, and the percentages of each of the cohorts who joined the 2XC discussions during this time period that are retained in subsequent months decline. Again, commenting frequency data are consistent with this pattern: there are steady declines across all commenting frequency levels in months subsequent to this period. This suggests that 2XC was not attracting new commenters at the rate at which it had previously, and that the few commenters that were joining were not especially loyal.

In May 2014, retention rates for previous cohorts increase temporarily, as a greater proportion of commenters from all previous cohorts participate in discussions than was the case in the months immediately prior to May 2014. There is also a sharp increase in the number of new commenters, as would be expected when the subreddit becomes visible to a large number of potential commenters. This cohort maintains a retention rate similar to the ones before it, despite the fact that it is several times as large as previous cohorts. In other words, May 2014 added a very large number of casual commenters who did not return, but also added a new core of loyal commenters that was proportional to its size, and therefore considerably larger than the loyal cores of previous smaller cohorts. Unlike the previous peak of loyalty in late 2011, this relatively high number of loyal commenters was maintained for many months, suggesting that in the months subsequent to May 2014, cohorts maintained a balance between large numbers of casual commenters who came and went, and sizable cores of loyal commenters who returned to comment in 5, 10, or 20 subsequent months.

In the first half of 2016, the number of unique commenters starts to grow significantly from month to month, reaching its apogee in January 2017 when 42,463 commenters contribute to 2XC discussions. This period coincided with the 2016 U.S. presidential election and its aftermath, an event that is significant to the interests of 2XC in several ways. The election featured the first female nominee of a major political party, and a Republican nominee who was known to have disparaged women and who, if elected, would likely nominate judges to the U.S. Supreme Court who opposed legal abortion. After Republican nominee Donald Trump was elected president in November 2016, women organized a protest march in Washington D.C., coinciding with Trump’s inauguration.

In February 2017, there is a steep decline in participation at all experience levels and in all cohorts. The number of commenters to 2XC declined to levels just below May 2014–January 2016 levels, suggesting that a new baseline of commenters had been established in May 2014 (between 20,000–25,000 commenters per month), which was added to by 10,000–20,000 commenters whose interest in contributing to 2XC coincided with the 2016 election.

From March 2017 to July 2018 (the last month in the data set), the number of 2XC commenters gradually increases, as do the number of contributors at various commenting frequency levels. This suggests that subsequent to the conclusion of the 2016 election, 2XC has rebuilt a new core of loyal contributors while simultaneously accruing an increasing number of casual commenters who do not return.

Assessing displacement

To determine the extent to which newcomers to 2XC displaced existing commenters in May 2014, we isolated the effects of several factors on the percentage of commenters from a given cohort that were retained in the months following May 2014. First, we took into account the extent to which cohorts diminish over time. It is likely, given the forces of attrition, that months that come later in a cohort’s history are likely to lower retention rates (Panek, et al., 2018). By controlling for the order in which a given month took place in the history of the cohort, we could account for this factor (order). Next, we controlled for the original size of each cohort (cohort size), as larger cohorts, we surmised, would be more likely to be comprised of casual commenters who were unlikely to be motivated to return. Additionally, we recognized that the 2016 election may have brought commenters from pre-May-2014 cohorts back into the fold, which might have negated any displacement effect occurring in May 2014. We also recognized that in May 2014, many commenters from pre-May-2014 cohorts returned to comment in May 2014 but then apparently left (most commenter cohorts show a spike in participation in May 2014 that declines immediately afterward). So as to isolate the displacement effect from these influences, we assessed the retention rates for cohorts from June 2014 to December 2015 and compared them to retention rates of those cohorts at other points in time. To facilitate comparison, we also made the number of months examined in each cohort equal to one another: we examined retention rates in the first 50 months of the 58 commenter cohorts originating between July 2009 and April 2014.

We entered three predictor variables in a linear regression equation: Order, Cohort Size, and whether or not a given month occurred in the 19 months subsequent to May 2014. The regression determined the extent to which each of these three variables contributed to variance in cohort retention rates.


Table 1: Regression results predicting monthly retention rates of commenter cohorts in r/TwoXChromosomes from July 2009 to July 2018.
Note: ***p<.001; n=2,900. Standardized coefficients are reported.
Model fit statistics: R2 = .65; Adjusted R2 = .68. Standard error of estimate = .05.
 Dependent variable
 Percentage of commenters retained
B (SE)
Overall number of commenters in 2XC that month (i.e., cohort size)-.46 (.001)***
Order-.65 (.001)***
June 2014 December 2015/Other months-.10 (.002)***


Results of the analysis (see Table 1) show unique effects of all three predictor variables. Order was highly negatively correlated with retention rate (B = -.63, p < .001); the later a month occurred in a history of a cohort, the smaller the percentage retained. Cohort size was highly negatively correlated with retention rate (B = -.46, p < .001); in larger cohorts, a smaller percentage of commenters returned to comment in subsequent months. There was also a small post-May-2014 effect (B = -.10, p < .001), such that in the 19 months after May 2014, cohorts retained fewer commenters than they did during months prior to or following that time period.

Discussion topics

To examine possible changes in discussion topics, we present several charts depicting the frequency with which concepts were observed in the 97 1,000-comment samples (July 2009 — July 2018). For ease of comprehension, we divided the concepts into seven charts (Figures 9a–9h). Each chart groups together several concepts that are related in some way, part of a particular domain or theme. For purposes of brevity, we review the clearest changes in frequencies as revealed by these charts.


Frequency with which gender-related topics occurred in 1,000-comment samples from r/TwoXChromosomes
Figure 9a: Frequency with which gender-related topics occurred in 1,000-comment samples from r/TwoXChromosomes.
Note: Larger version of Figure 9a available here.



Frequency with which appearance-related topics occurred in 1,000-comment samples from r/TwoXChromosomes
Figure 9b: Frequency with which appearance-related topics occurred in 1,000-comment samples from r/TwoXChromosomes.
Note: Larger version of Figure 9b available here.



Frequency with which motherhood-related topics occurred in 1,000-comment samples from r/TwoXChromosomes
Figure 9c: Frequency with which motherhood-related topics occurred in 1,000-comment samples from r/TwoXChromosomes.
Note: Larger version of Figure 9c available here.



Frequency with which sex-related or health-related topics occurred in 1,000-comment samples from r/TwoXChromosomes
Figure 9d: Frequency with which sex-related or health-related topics occurred in 1,000-comment samples from r/TwoXChromosomes.
Note: Larger version of Figure 9d available here.



Frequency with which family-related or relationship-related topics occurred in 1,000-comment samples from r/TwoXChromosomes
Figure 9e: Frequency with which family-related or relationship-related topics occurred in 1,000-comment samples from r/TwoXChromosomes.
Note: Larger version of Figure 9e available here.



Frequency with which school-related or work-related topics occurred in 1,000-comment samples from r/TwoXChromosomes
Figure 9f: Frequency with which school-related or work-related topics occurred in 1,000-comment samples from r/TwoXChromosomes.
Note: Larger version of Figure 9f available here.



Frequency with which meta-discussion topics occurred in 1,000-comment samples from r/TwoXChromosomes
Figure 9g: Frequency with which meta-discussion topics occurred in 1,000-comment samples from r/TwoXChromosomes.
Note: Larger version of Figure 9g available here.



Frequency with which belief-related or politics-related discussion topics occurred in 1,000-comment samples from r/TwoXChromosomes.
Figure 9h: Frequency with which belief-related or politics-related discussion topics occurred in 1,000-comment samples from r/TwoXChromosomes..
Note: Larger version of Figure 9h available here.


While some topics remain relatively consistent in their frequency over the entire observed period of time (sex; work), many other topics fluctuated in frequency over time. For example, topics relating to gender (see Figure 9a) are very frequent in the first stage of 2XC’s development, become less frequent until October 2011, at which point they become somewhat more frequent until May 2014. At this point, the topics double or treble in frequency, suggesting a change in the use of gender terms that corresponded with the addition of new contributors. During this time, the topics ‘sub’ (typically used as an abbreviation of ‘subreddit’) and ‘comment’ both become more frequent for a brief period of time (see Figure 9g). Subsequent to this time period, gender topics gradually decline in frequency until late 2017, when they experience another brief surge in frequency.

Topics relating to appearance (see Figure 9b) appear to decline over time. In the case of one of these concepts — ‘hair’ — the change in frequency corresponds roughly, though not precisely, with the addition of 2XC to the default subreddits in May 2014. ‘Hair’ is a relatively common topic of discussion until February 2014, after which point it is not discussed. In addition to these appearance-related topics, the topic of ‘friends’ occurs considerably less frequently after May 2014 (see Figure 9e). Conversely, topics relating to motherhood become more frequent over time (see Figure 9c). The topics ‘child/children’ and ‘birth’ are discussed relatively infrequently until mid-2014, after which they become more consistently frequent topics of discussion. In late 2017/early 2018, these topics experience a strong surge in frequency. Also in late 2017/early 2018, there is a surge in the frequency of topics relating to matters of politics, religion, or ethics, all of which were not present in early months (see Figure 9h).




Taken together, the findings of this study suggest that the addition of 2XC to the default subreddits precipitated a range of changes to the community, some of which persisted for years, and some of which did not. There is evidence to suggest that more experienced users were displaced by newcomers; however, it must be stressed that this effect was very small (B = -.10). Many factors influence whether or not first-time contributors to 2XC’s discourse return to comment again, not the least of which is time. As time passes, cohorts lose contributing members at a roughly hyperbolic rate. In nearly all of the cohorts examined, the majority of first-time commenters in any given month do not return to comment again. After two months have passed, more than 75 percent of the cohort typically have left. 2XC, like many online communities (Dabbish, et al., 2012; Davidson, et al., 2019), is in a continual state of renewal, losing all but a small core of, at most, a few hundred loyal commenters. These high turnover rates in online communities are not necessarily bad; Dabbish and colleagues (2012) find that high turnover can convey a sense of liveliness or activity that attracts newcomers, especially when community contributors share a sense of common identity. Though 2XC possesses a years-long history and a kind of ‘cultural memory’ that is preserved in its archived discourse, the relatively short duration of the average commenters’ cycle of contributions makes it unlikely to be significantly disrupted by any particular event.

It is also important to recognize the context in which 2XC was added to the defaults. In April 2014, 2XC was not a flourishing community in the sense that it was not attracting as many new commenters as it once had, and the commenters that were joining at the time were less likely to return than had previously been the case. The addition to the defaults had a small displacing effect, but without the infusion of new, loyal commenters that it brought, it seems likely that the subreddit would have languished. In addition to the effect of the passage of time, a factor that is external to the subreddit — the 2016 U.S. election — had a profound-but-temporary effect on the community. Many existing contributors returned to discussions in 2016 or continued to participate for more months than would otherwise be expected. However, after the presidential inauguration in January 2017, retention rates for all cohorts dropped sharply. In fact, this sharp decline in cohort retention more closely resembled the expected displacement effect than the effect we observed. If any event signaled an exodus of existing, loyal commenters from 2XC, it was not the addition of 2XC to the default subreddits, but the end of the 2016 election and its immediate aftermath.

Keeping in mind that the vast majority of contributors from a given cohort do not continue to contribute for more than a few months, the persistence of popular topics reflects a kind of persistent community norm rather than the interests of particular users. Such persistently popular topics are indicative of commonalities between past contributors with the ones that replace them, a common identity linked to the venue rather than the transient groups of users that inhabit it. When topics become more or less popular, it suggests that the norm has shifted, and that the contributors who replace past contributors do not share some interests. Concurrent with the influx of newcomers to 2XC’s discourse, the data show consistent frequency of some topics — such as sex, rape, and work — but changes in frequency in others — such as hair, friends, and children.

Gender topics (e.g., woman/women, man/men), which frequently occurred when the subreddit was first created and immediately after May 2014, correspond to periods of invention, or re-invention, in the history of 2XC. It is possible that such topics are discussed as the community establishes, and then re-establishes, its identity. As 2XC becomes more stable and the retention rates climb, perhaps the shared ideas about gender become ‘taken for granted.’ The nadir in the frequency with which these topics occurred corresponded to the high point of cohort retention rates (late 2011). Contributors are free to talk less about gender as an aspect of their identities or about women or men in the aggregate, and more about their interests and experiences.

Just as external events drive patterns of participation, so too do they influence topics of discourse. The changes in popular topics in late 2017 corresponds to the contentious nomination of Brett Kavanaugh to the U.S. Supreme Court. Kavanaugh was accused by multiple women of sexual assault or misconduct. It is likely that this event drove the discussion toward topics relating to law, sexual assault, and feminism. Additionally, surges in the frequency of topics relating to birth or children were likely a part of discussions of abortion, as Kavanaugh’s confirmation as Supreme Court judge was seen by many as a likely precursor to the overturning of the laws protecting women’s access to safe, legal abortion.

Overall, there is little evidence that the changes wrought by the addition of 2XC to the default subreddits permanently shifted the focus of the group away from the experiences and perspectives of women. Rather, after a relatively brief period of disruption, a new community of women with a different set of concerns, many of which reflect a kind of outward turn toward the political/public sphere, began to take root in 2015. Prior ethnographic research on 2XC conducted prior to addition to the defaults (Workman and Coleman, 2014) found that 2XC contributors viewed it as an inclusive ‘safe space’ where girls and women could be insulated from the hostile, male-dominated rhetoric of many other subreddits. Our findings suggest that 2XC remained a space for discussions relating to girls’ and women’s experiences after a sudden influx of newcomers, but that the topics of these discussions reflected a new set of interests. They suggest that despite the evoking of the single biological attribute of chromosomes in the title of the subreddit (r/TwoXChromosomes), contributors in 2XC’s discourse express their identities in a range of ways. Popular discussion topics evoke motherhood or citizenship while eliding categories of race and class. While it is important to understand 2XC in the context of the gender power dynamic online, a dynamic which often replicates off-line inequities (Herring, 2003), it is equally important to recognize differences among female-identifying contributors and potential contributors, and to understand how those differences manifest themselves in popular topics of discussion in online communities such as 2XC. This study is intended to be understood as a case study. In its approach to understanding the impact of a sudden influx of newcomers to an online community, it examines a larger number of users for a longer duration than many qualitative studies of this phenomenon (e.g., Yeshua-Katz, 2016). Though previous studies have used case studies as a way to understand the impact of newcomers to online communities (e.g., Honeycutt, 2005), many of these case studies pre-date the widespread adoption of the Internet and the subsequent growth of online communities. The present study permits a better understanding of the effects of rapid growth in the era of widespread Internet and social media adoption.

This study is intended to serve as an example of how researchers might examine such changes over long periods of time, and not as a definitive account of displacement effects in all possible contexts. The content analysis for this study was rudimentary, and did not examine sentiment or context of usage or particular terms. Though we can be reasonably certain that contributors to 2XC discussed the topic of children more frequently subsequent to May 2014, we cannot know what they had to say about this topic without a more in-depth analysis. In-depth analysis of the content would do well to examine a portion of the comments using qualitative methods so as to better understand the meaning of the discourse and how it changed over time. Lastly, the study takes a narrow view toward community, ignoring the role of those who visit 2XC but did not contribute to its discourse. Further research could examine the experiences of these other users and determine whether the changes in discourse that followed May 2014 corresponded to a difference in readership of the comments.




While some online community members go to great efforts to attract new contributors, others are circumspect of the benefits they bring to the community. Through empirical research studies such as the present study, we may identify the types of changes that occur when a large number of new contributors join the discussions. This case study demonstrates an instance in which a topic-oriented online community remains robust long after such a sudden change, though changes to its discourse precipitated by this change appear to last. 2XC remained a place where Internet users could discuss the experiences and issues important to girls and women, but the analysis made it clear that different girls and women prefer to discuss different topics at different times. There is little evidence that the influx of newcomers forced women out, but there is evidence that the community became more outwardly focused in its wake, a trend that was reinforced by the election of Donald Trump and the appointment of Brett Kavanaugh to the Supreme Court. Though there may be no recovering the earlier version of the community, its replacement appears no less legitimate. End of article


About the authors

Dr. Elliot Panek studies the uses and effects of digital media from sociological and psychological perspectives. He has published research on the social dynamics of online communities, social media and narcissism, and media addiction.
Direct comments to: epanek [at] ua [dot] edu

Wyatt Harrison is an undergraduate student at the University of Alabama, studying management information systems.
E-mail: wvharrison [at] crimson [dot] ua [dot] edu

Jue Hou is a Ph.D candidate in the College of Communication and Information Sciences at the University of Alabama.
E-mail: jhou7 [at] crimson [dot] ua [dot] edu



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Concepts derived by Leximancer software from 1,000–comment monthly samples from July 2009 — July 2018 in the r/TwoXChromosome subreddit.
Note: Discussion topics are listed in bold.
downidea someoneyear
equalityimportant sorry 
 instead sounds 



Editorial history

Received 25 June 2019; revised 15 August 2019; accepted 28 August 2019.

Creative Commons License
This paper is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Change by default: Exploring the effects of a sudden influx of newcomers on the discourse of r/TwoXChromosomes
by Elliot Panek, Wyatt Harrison, and Jue Hou.
First Monday, Volume 24, Number 10 - 7 October 2019

A Great Cities Initiative of the University of Illinois at Chicago University Library.

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