Grok curates timelines

X is putting Grok in charge of more of the feed, starting with custom timelines for some paying users on iPhone. (theverge.com) X product head Nikita Bier said on April 22 that Premium subscribers on iOS can get early access to pin topic-based timelines to the home tab, and Grok will choose which posts fill them. The Verge reported the feature as a new feed curation option inside X itself. (theverge.com) TechCrunch reported the new timelines cover more than 75 topics and are replacing Communities in at least some parts of the app, with Grok-built feeds and new ad inventory alongside them. MacRumors separately reported the rollout began on iOS on April 22 for Premium users. (techcrunch.com, macrumors.com) At the same time, Grok users spent April 22 and April 23 reporting “High Demand” errors that blocked text generation for free and paid accounts. PiunikaWeb said the outage-like behavior had lasted roughly 24 hours by April 22, while other reports tied the strain to heavy usage across xAI’s services. (piunikaweb.com, ibtimes.sg) That puts two changes on the platform at once: Grok is moving from chatbot to traffic shaper just as access to the bot itself looks uneven. The new timelines let X users ask an artificial intelligence system to rank posts around a topic, not just answer a prompt in a chat box. (theverge.com, techcrunch.com) X and xAI have been tightening that link for months. xAI said in November 2025 that Grok 4.1 was rolling out across grok.com, X, and the iOS and Android apps, and its developer docs now point customers to Grok 4.20 as the flagship model. (x.ai, docs.x.ai) The company has not publicly detailed how Grok will balance relevance, recency, engagement, or viewpoint diversity inside these timelines. TechCrunch said the feeds can also carry ads, which means the recommendation system is being attached directly to monetized placement. (techcrunch.com) X has pitched the feature as a way to follow niche interests without manually building lists or searching for posts. The Verge said users can pin specific topics and let Grok keep the stream updated from there. (theverge.com) For now, the rollout looks small, paid, and iPhone-first, while the complaints are broad and immediate. Grok is being asked to decide more of what people see on X at the same moment many users say they cannot reliably use it. (theverge.com, piunikaweb.com)