Kevin Indig, an independent SEO analyst, reviewed roughly 35,000 ChatGPT citation URLs for G2 in February 2026. He found that user-generated content platforms hold 17.1 percent of non-vendor cited-domain share in ChatGPT’s answers to SaaS buyer prompts, versus 4.0 percent for publishers. The sample is narrow by design: one engine, one market, one month, ChatGPT only, US only, December 2025. Indig’s own tracking found 91 percent of citations in this category of prompt appear in only one AI engine, so the pattern describes ChatGPT’s SaaS answers specifically, not AI search as a whole.
Indig published the piece as a contributor column syndicated from his own site, not as original Search Engine Land reporting, though the outlet’s editorial staff reviewed it before republication. He pulled the citation data from Profound, a tool that tracks which domains large language models cite, then sorted each citation’s root domain into one of four buckets: review platform, UGC platform, publisher, or vendor. Prompts were also tagged by buyer-journey stage: discovery, exploration, evaluation, or focused evaluation.
Vendor domains took the largest slice at every stage, running from 66.7 percent to 71.8 percent of citations, unsurprising since the prompt set was built to surface software vendors. Those two figures, 17.1 percent and 4.0 percent, describe what remains once vendor domains are stripped out. They measure a share of third-party, non-vendor citations, not a share of every citation in the dataset.
That third-party share concentrates hard. Wikipedia, Reddit, and LinkedIn account for 99 percent of the citations inside the UGC bucket, with every other UGC platform splitting the remaining 1 percent. Wikipedia by itself contributes between 10.1 and 14.0 percentage points to that 17-point UGC floor across the four journey stages, outsizing the entire review platform category at every stage except evaluation.
Review platforms move with the buyer’s stage. Their share climbs from 7.4 percent at discovery to 13.2 percent at evaluation, then falls to 8.4 percent at focused evaluation, a 5.8-point swing. UGC barely shifts, ranging from 15.1 percent to 18.2 percent across the same four stages, a 3.1-point spread. Review sites do their heaviest work while a buyer builds a shortlist. UGC holds steady through every stage instead.
The floor is stable in aggregate but not underneath. Reddit’s visibility fell 11.7 percent and its AI mentions fell 10.9 percent in the 28 days to June 8, 2026, by Indig’s tracking. Three weeks later the trend reversed: LinkedIn’s SEO visibility rose 43.3 percent and Reddit’s rose 18.1 percent. Across that same reversal window, each platform’s AI Overview citation count fell during the stretch its organic numbers climbed.
Google added platform properties to Search Console on July 7, reporting clicks, impressions, and average position for Instagram, TikTok, X, and YouTube. Reddit and LinkedIn are absent from that list, the pair carrying the heaviest UGC citation load in Indig’s data. The new tool also measures Search and Discover performance, not AI-answer citations, so the two data sets still have to be joined by hand.
For a search team, the practical read is that a meaningful share of the work behind a ChatGPT citation happens on properties the team does not own. That includes a Reddit thread, a Wikipedia source list, and a LinkedIn post from a named employee rather than a brand page. Indig’s data shows where that share concentrates; it does not prove causation for any single post. The aggregate holds steady while individual platforms swing underneath it.
Teams that already budget for digital PR and review-site placement should add a third line for community presence, tracked as one aggregate number, and revisit the platform mix each quarter rather than assume last quarter’s composition still holds.
Search Engine Land published Kevin Indig’s contributor analysis, syndicated from his own site, on August 12, 2026.
