Signal Study Maps 18 "Species" of Bots Across the Reddit Ecosystem

Summary

Researchers analyzed a dataset of 3,389 identified bots and their complete activity histories to build a taxonomy of automated agents operating on Reddit. Clustering analysis identified 18 distinct bot "species," spanning content-specialized bots, behavior-driven bots, and infrastructural roles such as moderation and utility support. Temporal analysis found that bot numbers and activity expanded rapidly and peaked around the COVID-19 period, then began declining even before Reddit's 2023 API policy changes that are often cited as the cause of bot reduction. Despite the decline in volume, the overall diversity of bot species has remained remarkably stable over time. The researchers frame these findings as evidence that online bot populations form evolving digital ecosystems rather than a monolithic or static category.