🔬 Research Summary by Rachel Krohn, an assistant professor of computer science at the Rose-Hulman Institute of Technology, specializing in online social media dynamics.
[Original paper by Rachel Krohn and Tim Weninger]
Overview: On Reddit, subreddit links are often used to directly reference another community. This use potentially drives traffic or interest to the linked subreddit. To understand and explore this phenomena, we performed an extensive observational study. We found that subreddit links not only drive activity within referenced subreddits, but also contribute to the creation of new communities. These links therefore give users the power to shape the organization of content online.
Content on Reddit is organized into thousands of subreddits – defined communities with unique and specific purposes. Because these subreddits are user-created, the landscape of Reddit is constantly evolving. One factor is the subreddit link, which allows users to reference a subreddit directly. By analyzing these subreddit links, we sought to better understand this complex and nuanced communication method.
RQ1: Do subreddit links spur the creation of new communities?
We found that subreddit links are a significant driver of new subreddit creation. A simple joke, if well-placed and well-timed, can lead to the birth of a new, thriving community.
RQ2: Does a subreddit link impact the activity level of the referenced community?
Yes! When links reference a particular subreddit, that referenced subreddit typically sees an influx of interest and new attention — presumably from users following the link.
RQ3: From the perspective of these subreddit links, how has the landscape of subreddit interactions changed over time? What does this tell us about the evolution of Reddit?
Over time, we have found that the subreddit link network has become less dense, as the creation of new communities is growing faster than the creation of links.
Overall, we found that Reddit users have embraced the subreddit link as a mechanism for promotion, humor, and innovation, spurring wide-scale evolution in the community landscape.
What are subreddit links?
Unlike other user-centric social media platforms, Reddit is built around subreddit-communities. Each subreddit is a defined community, with a specific purpose and topic. Because any user can create a new subreddit at any time, Reddit is host to a wide variety of communities – from the serious to the weird. For example, r/science is “a place to share and discuss new scientific research”, while r/ShowerOrange is “dedicated to the consumption of various citrus fruits whilst taking a shower.” Because all subreddits must coexist and compete for users, the subreddit link has evolved as one method of communication and promotion between these communities.
Unlike typical Web hyperlinks, which reference a single item of interest on the Web, a subreddit link references the community as a whole, not just a specific post or Web page. Although most subreddit links reference an existing community, many actually point to a community that does not exist – yet.
These subreddit links are an accepted form of communication on Reddit, with many comments consisting solely of a subreddit link. These links serve as a shorthand to reference a related community (ie, linking to r/dataisbeautiful from r/data), or to comment on the contents of a post (ie, linking to r/mapswithoutnewzealand when a map or globe has mistakenly left out the island nation of New Zealand). But subreddit links have also evolved beyond their original purpose, and now also serve as a medium for extended collaborative jokes. For example, a link to r/mapswithoutnewzealand may be followed by r/mapswithoutjamaica, r/mapswithoutsvalbard, or r/mapswithoutthecheasapeakebay – whether or not these geographical features are actually missing from the map.
Because of the ubiquity of subreddit links, and their predictable format, they are well-suited to an observational study. By analyzing the frequency, timing, and impact of these user-created artifacts, we can better understand the mechanisms behind collaborative internet use.
Impact of Subreddit Links
Most subreddit links reference an existing community. For these types of links, we find that the referenced subreddit experiences an increase in activity surrounding the time of the link. Although some links lead to increased activity in the community following the link, other links are in response to an already active community. We call these proactive and reactive links, respectively. Surprisingly, subreddit size does not determine whether a link is typically proactive or reactive. We did find, however, that linking subreddits tend to be larger than the referenced subreddit; this supports the theory that one use for subreddit links is to promote a smaller community to a wider pool of users.
Other subreddit links reference a community that does not yet exist. In these cases, users who click the link will be presented with an error – and the option to create a new subreddit with that name. We found that these inventive links are a significant driver of new community creation, with 10% of all subreddits being created within one week of a subreddit link to the nonexistent community. This is an accepted phenomenon on Reddit, with multiple communities like r/birthofasub dedicated to chronicling the creation of new subreddits following a link event.
The Landscape of Reddit Communities
To determine how the community landscape has changed on Reddit over time, we construct a graph of subreddit links. By examining a snapshot of this graph at a particular time, and comparing it to a later version, we can gain insight into the changing role of subreddits. This subreddit linkage graph has grown over time, as new communities are created and contribute their own links to the graph. The graph has also become sparser and more tree-like over time, indicating that, typically, communities are not as strongly tied to one another as they were in the past. Taken together, this portion of the study paints a picture of an increasingly specialized community landscape wherein users seek out smaller, more niche communities instead of large popular ones.
Between the lines
Prevention of misinformation and social media manipulation is critically important. Our findings reveal that subreddit links drive the creation of new communities, and increased activity in existing ones. Individual bad actors or coordinated groups could therefore exploit this mechanism to push a malicious agenda or viewpoint. Alternatively, these subreddit links could be used for good by driving traffic to fact-checked sources to combat misinformation and disinformation online.
Because this study was limited in scope, further research is required. A similar approach could be applied to other social media platforms, like Facebook and Twitter. Now that we know the extent to which subreddit links can drive traffic and spawn new communities, we need to determine why that is the case.
What types of users are creating these links? Do users who follow subreddit links become active members of the community, or are they just passing through? Do certain characteristics – like timing, location, and score – predict the effectiveness of a subreddit link? It is important that we determine the true motivations and impacts of these links, and the potential consequences within.