Threats to the sustainability of Community Notes on X
Zahra Arjmandi-Lari, Alexios Mantzarlis, Tom Stafford
TL;DR
This paper investigates the sustainability of X's Community Notes by analyzing contributor behavior and the causal impact of note publication. It employs a regression discontinuity design around the publication threshold of $0.4$ to estimate how having a note published affects future note-writing, revealing a small but robust $"$ $5\%$ increase in subsequent contributions$"$ for near-threshold authors. Key findings show rapid growth and high concentration of activity among a small subset of power users, substantial churn among authors, and a large share of notes remaining unseen due to ratings diversity requirements, underscoring systemic sustainability risks. The work also discusses implications for broader adoption of crowd-sourced moderation and the potential effects of AI-generated notes on human participation.
Abstract
Community Notes are emerging as an important option for content moderation. The Community Notes system pioneered by Twitter, now known as X, uses a bridging algorithm to identify user-generated context with upvotes across political divides, supposedly spinning consensual gold from partisan straw. It is important to understand the nature of the community behind Community Notes, especially as the feature has now been imitated by several billion-user platforms. We look for signs of stability and disruption in the X Community Notes community and interrogate the motivations other than partisan animus (Allen, Martel, and Rand 2022) which may be driving users to contribute. We conduct a novel analysis of the impact of having a note published, which requires being considered "helpful" by the bridging algorithm, utilising a regression discontinuity design. This allows stronger causal inference than conventional methods used with observational data. Our analysis shows the positive effect on future note authoring of having a note published. This highlights the risk of the current system, where the proportion of notes considered "helpful" (and therefore shown to users on X) is low, 10%, and declining. This analysis has implications for the future of Community Notes on X and the extension of this approach to other platforms.
