Science, AskScience, and BadScience: On the Coexistence of Highly Related Communities

TL;DR

This paper analyzes the coexistence and interactions of highly related online communities on Reddit, revealing user engagement patterns and community formation behaviors over an 8-year period.

Contribution

It introduces a taxonomy of affixes used to create related communities and provides empirical insights into user attention allocation and community dynamics.

Findings

Users active in newer communities tend to be more engaged in original communities.

Identifies common affixes used to form related communities.

Provides a taxonomy of community relations based on user behavior.

Abstract

When large social-media platforms allow users to easily form and self-organize into interest groups, highly related communities can arise. For example, the Reddit site hosts not just a group called food, but also HealthyFood, foodhacks, foodporn, and cooking, among others. Are these highly related communities created for similar classes of reasons (e.g., to focus on a subtopic, to create a place for allegedly more "high-minded" discourse, etc.)? How do users allocate attention between such close alternatives when they are available or emerge over time? Are there different types of relations between close alternatives such as sharing many users vs. a new community drawing away members of an older one vs. a splinter group failing to cohere into a viable separate community? We investigate the interactions between highly related communities using data from reddit.com consisting of 975M posts and comments spanning an 8-year period. We identify a set of typical affixes that users adopt to create highly related communities and build a taxonomy of affixes. One interesting finding regarding users' behavior is: after a newer community is created, for several types of highly-related community pairs, users that engage in a newer community tend to be more active in their original community than users that do not explore, even when controlling for previous level of engagement.