Data: Pew Research Center; Note: Survey was conducted by phone only in 2021, and by web, mail and phone in 2025; Chart: Kavya Beheraj/AxiosAmericans' social media habits are splintering in ways that echo the fractured traditional news landscape, according to a new Pew Research Center report.Why it matters: The same fragmentation that reshaped news is now reshaping social media, making it harder for companies, brands and public figures to reliably reach large swaths of the public.By the numbers: Pew Research Center surveyed 5,022 U.S. adults between Feb. 5 and June 18, and found that YouTube (84%), Facebook (71%) and Instagram (50%) remain the most widely used social platforms.Between the lines: Facebook, YouTube and Instagram are some of the earliest platforms, having all been founded between 2004 and 2010, and thus have had more time to become part of a person's routine or media diet. Reddit and Twitter, now known as X, were also founded in 2005 and 2006, respectively, but have smaller user bases.Yes, but: While the number of X users in the U.S. has decreased since 2021, Reddit has seen an uptick, according to the Pew survey.26% report using Reddit today, compared to 18% four years ago. Reddit is most popular among those ages 18-29, with roughly half saying they use the platform regularly. Zoom in: YouTube remains the most widely used platform among U.S. teens and those ages 18-29 (95%) and 30-49 (92%), though TikTok is on the rise. 63% of those under 30 use the short-form video platform regularly and roughly half say they go on TikTok at least once a day.A majority of those under 30 (58%) are also active on Snapchat, the report finds. Meanwhile, Truth Social (1%), Bluesky (6%) and Threads (15%) are the least used platforms among young people. Of note: WhatsApp is also steadily increasing in popularity among U.S. social media users — with 32% saying they use the platform, up from 23% in 2021. It is most popular among Asian and Hispanic users, per the report. What to watch: Content on social media platforms is increasingly informing large language models like ChatGPT and Gemini. According to a recent Muck Rack report, Google's LLM, Gemini, is most likely to cite content or pull transcripts from YouTube. Reddit remains a top source for ChatGPT, Perplexity and Google AI overviews, according to research by marketing platform Profound. More on Axios: Brands turn to Reddit as AI makes it impossible to ignoreWhat news sources AI chatbots read