Audit: Reddit AI search favors formal, highly upvoted comments
What this answers
- Does Reddit's AI search favor popular comments over personal ones?
- Yes. A University of Illinois Urbana-Champaign audit of 30,000 Reddit AI search answers found comments a standard deviation more formal had 49% higher odds of selection, while personal-experience language cut the odds to 0.789.
- How much does a comment's vote count affect whether Reddit's AI search picks it?
- A lot: selected comments had a median vote ranking at the 91st percentile within their thread, versus the 45th percentile for comments that weren't selected, per the audit.
A preprint audit by University of Illinois Urbana-Champaign researchers traced 30,000 Reddit AI search answers back through 14.68 million comments across 20 advice subreddits. Comments one standard deviation more formal had 49% higher odds of being selected, while personal-experience language lowered the odds to 0.789; first-person words like “I” and “my” fell from 3.3% of quoted comments to 0.06% of final answers, per the study, reported by Search Engine Journal. The study has not been peer reviewed.
Why it matters: The audit suggests Reddit's own AI search rewards formal, already-popular phrasing and strips out first-person language, a selection bias distinct from how outside engines like ChatGPT and Google cite Reddit.
The record: Reddit
Posted to the wire September 17, 2026. Edited by Joe Balewski.