Bluesky is not alone in employing artificial intelligence to craft personalized content streams. This week, amid several new product announcements, X introduced Grok-powered Custom Timelines. This feature allows users to explore one of more than 75 specific topics through curated feeds that can be pinned directly to the home tab. The company described the launch as one of the "biggest changes" ever made to the app, explaining that Grok's AI is used both to construct these custom timelines and to tailor them to individual users. These new feeds arrive concurrently with X's decision to shut down X Communities, a feature that enabled user-created, member-based groups around various topics but had experienced declining engagement.

On the platform, X's head of product, Nikita Bier, pointed out that the custom timelines perform especially well for topics with which a user already interacts. The company clarified that Grok analyzes every post, comprehends its content, and then applies relevant topic labels. This capability is powered by AI models from xAI, the company that acquired X last year, further integrating the two services. At launch, custom timelines are exclusively available to Premium subscribers on iOS, with Android support currently in development. The feature is accessible across all Premium subscription tiers.

To use the feature, users simply scroll to the right past their "For You" and "Following" feeds, as well as any other pinned personal lists. Then, they tap the plus (+) sign to select which custom timelines to pin to the home tab. It's important to choose carefully, as there is a limit of only ten topics or lists that can be pinned.

Users can also reorder their selected topics directly from the same screen.

Once pinned, these feeds can be tapped from the home tab across platforms to browse the curated content. Notably, the second position in each feed tested was occupied by an advertisement, indicating X may have discovered a new method to expand its ad inventory. This is significant, as X's advertising business has reportedly faced challenges since Elon Musk's acquisition, with mixed reports on whether the situation has improved.

**X’s custom timelines offer 75+ category options**

The initial topics are broad and fairly conventional, resembling the high-level sections found on many news websites. Categories include Business & Finance, Sports, Technology, Politics, Stocks & Economy, News, Science, Movies & TV, Food & Drink, Art, Real Estate, Home & Garden, Beauty, Education, and Gaming. Beyond the general sports category, users can follow specific sports such as American football, baseball, basketball, boxing, soccer, golf, MMA & wrestling, racing & motorsports, rugby, snow sports, ice hockey, tennis, cricket, Formula 1, cycling, and the Olympics. E-sports is also an available option.

Pop culture and technology topics constitute a large portion of the categories. Pop culture options include celebs, music, concerts, country music, dance, electronic music, fashion, pop, K-pop, J-pop, podcasts, hip hop, and jazz. Alongside the general Technology category, users can follow specialized interests like Artificial Intelligence and Cryptocurrency, which are consistently popular on the platform. Additional categories align with Elon Musk's various business and personal interests, such as robotics, software development, space, and biotech.

Other general categories encompass anime, digital art, photography, career, pets, design, marriage & family, shopping, and mental health.

**News Categories: War, Crime, and Elections**

It is worth noting that the initial set of news-related topics prominently suggests the Iran Conflict, Crime, and Elections at the top of the list. While this likely mirrors current discussions on X, it also demonstrates how product design can influence the news users encounter. A more organized approach might involve grouping the dozens of options into broader, alphabetized high-level categories, with subcategories appearing upon selection. This would allow X to significantly expand its "news" categories beyond these three major topics.

There may also be concerns about these timelines being built by Grok, an AI ostensibly created to be politically neutral and "truth-seeking" but which has, in practice, sometimes exhibited a rightward bias or amplified misinformation. In limited testing, however, the custom timelines did not display an obvious political leaning. During several test scrolls, the feeds aggregated content from a diverse range of outlets including ABC, CBS, CSPAN, AP, Reuters, AFP, Daily Beast, The Hill, Foreign Policy, Puck, The Atlantic, The Economist, Bloomberg, Al Jazeera, Forbes, and the BBC—many of which the tester does not follow—alongside commentary from various pundits.

Whether these custom feeds will substantially alter how people use X is yet to be determined. Typically, users prefer to see content they care about within their main algorithmic feed. However, custom feeds do facilitate exploring new interests or diving into topics only when they are relevant, such as checking a sports feed during a game. Combined with X's new "Snooze Topics" option for the For You feed, users can now more precisely customize their experience on the platform.