Bluesky isn’t the only company leaning into AI to help build custom feeds, it seems. Amid a slate of recent product releases , X this week announced the launch of Grok-powered Custom Timelines, which let you dive into one of over 75 specific topics through curated feeds that can be pinned to your home tab. The company touted the feature as one of the “biggest changes” to the app to date, saying it uses Grok’s AI to not only build these custom timelines but also personalize them for individual users. The custom feeds are arriving at the same time as X has announced it is shutting down X Communities , a feature that had allowed people to create their own member-based communities around various topics, but saw declining use. Today we're announcing two product changes for organizing communities on X: 1. XChat now supports joinable links for groupchats. Create a public link & share direct to Timeline.…