X has replaced its Communities feature with AI-powered custom feeds curated by Grok, the company's in-house AI model. The new system lets users build personalized timelines around specific topics, but unlike Communities, the content is assembled algorithmically rather than driven by member participation.
The practical difference matters. Communities worked like group feeds - members actively posted around a shared topic, and you saw that content because you joined the group. Grok-curated feeds work more like discovery engines: the AI assembles posts it predicts you'll engage with, based on your behavior and content signals. You're not getting a community; you're getting a personalized broadcast.
New ad slots come with the rollout. X has embedded advertising directly into the custom feed format, consistent with the company's pattern of monetizing each new surface it ships. The feeds are not a content discovery experiment running on goodwill.
For users, the central question is whether Grok's curation beats human-organized Communities at surfacing relevant content. Communities had one clear advantage: you knew why something appeared. With Grok feeds, the logic is opaque. If the algorithm keeps surfacing content you didn't ask for - or filtering out content you did - there's no obvious way to understand why, let alone correct it.
This follows a broader shift across social platforms. Instagram, LinkedIn, and YouTube have all moved toward AI-curated discovery over community-driven feeds. Whether users prefer algorithmic assembly over groups they've actively chosen is still genuinely open - platforms share engagement data selectively, and high engagement doesn't always mean users are getting what they actually want.