User-Generated Content is AI's Top Third-Party Source

User-generated content (UGC) platforms represent the largest third-party source of citations for AI models like ChatGPT when responding to Software as a Service (SaaS)-related prompts, according to an analysis conducted for G2 in February 2026. Across a sample of approximately 35,000 ChatGPT citations captured in Profound, UGC platforms collectively held a greater share of cited-domain authority than review sites and publishers combined. This dominance was observed across all stages of the user journey, from initial discovery to focused evaluation, indicating that users consistently rely on UGC for information regardless of their stage in the decision-making process.

The analysis focused on ChatGPT usage within the United States during December 2025, examining SaaS vendor-related prompts. These prompts were categorized into four journey steps: discovery (376 prompts), exploration (1,179 prompts), evaluation (1,367 prompts), and focused evaluation (255 prompts). Each citation URL was reduced to its root domain and classified into one of four categories: review_platform, ugc_platform, publisher, or vendor_or_other. To ensure data integrity, records were de-duplicated to count only one citation per prompt and domain combination, even if multiple threads from the same platform were cited.

Notably, the evaluation stage comprised the largest portion of the prompt set analyzed. The study also found that over half of the SaaS-related prompts utilized commercial language, yet only a small fraction, specifically 1.5%, explicitly named a vendor brand. This suggests that AI models are frequently used for comparative and research purposes without direct brand queries, relying heavily on broader information sources.

While the aggregate data highlights the significant influence of UGC, the analysis acknowledges limitations in its broad categorization. The UGC set encompasses diverse platforms such as Reddit, Wikipedia, Quora, YouTube, and LinkedIn, each serving distinct user bases and purposes. The study reports on this UGC set in aggregate for its stage analysis but plans to break out the specific composition of these platforms in a later section. The challenge for brands lies in building authority within these user-controlled environments, where direct influence is limited. Platforms like Reddit, in particular, are identified as being exceptionally difficult to influence, underscoring the unique nature of UGC as an AI information source.