X Fixed a Ranking Bug That Was Hiding Your Friends in Replies
Mutual-follow data was simply missing from the algo. One fix later, your friends are supposed to show up again.
X updated its ranking algorithm Monday to surface replies from mutual followers - people who follow each other - higher in reply threads. Nikita Bier, X's head of product, announced the change directly on X, saying mutual-follow data had been missing from the X algorithm entirely. Without that signal, the platform ranked replies from complete strangers at the same level as replies from accounts you follow back. Bier described the outcome as replies feeling "like a battleground with people you don't recognize."
Mutual-follow ranking now applies a score boost when both the post author and the viewer follow each other. A mutual's reply climbs above a non-mutual's reply even if the non-mutual has more engagement. Bier also noted the change should help "clusters form around interests more easily" - meaning niche communities should surface more visibly to each other without X needing to build a separate group product to make it happen.
A Missing Signal - Not a Policy Reversal
Framing matters here. Bier said the mutual-follow data was "missing from the algo" - not that X had previously weighted it and then removed it. Nobody decided to hide your friends. The signal was never there. For developers building on the X API who model reply engagement or train ranking systems on X data, this is worth noting: reply ordering now includes a mutual-follow input it did not have before, and any model trained on prior reply data will no longer reflect how the X algorithm ranks replies today.
X has been pushing a series of changes aimed at rewarding original creators and keeping them posting. X launched a video editor for iOS earlier this month with multilingual captions and a green screen tool designed to encourage original content over reposts. Before that, X changed its creator compensation model to favor original posts over accounts that aggregate other people's content. Surfacing replies from people you actually know fits that same direction - engagement routed through existing relationships rather than algorithmic strangers.
Threads has been running a similar playbook from the competitor side - adding co-hosted live chats, translation features, and a private feed control called "Your Algo" that lets users shape what appears in their timeline. Threads reached 500 million monthly active users in June. X fixing a years-old gap in its reply ranking is not a response to Threads specifically, but both platforms are now chasing the same thing: giving users back the sense of community they expected when they followed people in the first place. Whether one bug fix closes that gap is a different question.
