  Fears about the destabilizing impact of misinformation online have motivated
individuals and platforms to respond. Individuals have become empowered to
challenge others' online claims with fact-checks in pursuit of a healthier
information ecosystem and to break down echo chambers of self-reinforcing
opinion. Using Twitter data, here we show the consequences of individual
misinformation tagging: tagged posters had explored novel political information
and expanded topical interests immediately prior, but being tagged caused
posters to retreat into information bubbles. These unintended consequences were
softened by a collective verification system for misinformation moderation. In
Twitter's new platform, Community Notes, misinformation tagging was
peer-reviewed by other fact-checkers before exposure to the poster. With
collective misinformation tagging, posters were less likely to retreat from
diverse information engagement. Detailed comparison suggests differences in
toxicity, sentiment, readability, and delay in individual versus collective
misinformation tagging messages. These findings provide evidence for
differential impacts from individual versus collective moderation strategies on
the diversity of information engagement and mobility across the information
ecosystem.
