Across studies of hundreds of millions of AI citations, Reddit and YouTube lead, followed by review platforms, direct-answer brand pages, Wikipedia, LinkedIn for B2B, press, and the niche forums of each category. The long tail is huge: most citations spread across thousands of smaller sites.
Reddit is the most cited source across engines, with roughly 40% frequency in one 680-million-citation index. YouTube leads inside Google AI Overviews and shows the strongest single correlation with AI visibility. Review platforms come next, then your own direct-answer pages, Wikipedia, LinkedIn for professional queries, editorial press, which drives about 27% of citations and up to 49% on time-sensitive questions, then niche forums, with Facebook and other social far behind.
About 95% of citations spread across thousands of smaller domains, so the specialist sites of your category, the perfume forums, the local guides, the industry directories, often decide who gets named for its buyer questions. They are also far easier to enter than Wikipedia or national press.
The mix shifts fast: ChatGPT's Reddit share once fell from about 60% to 10% within six weeks after a platform change. The safe strategy is spreading across layers and re-checking the map continuously, which is exactly what a daily scan is for.