Facebook is introducing better comments for pages by enabling threaded comments and surfacing the most interesting ones. The idea is to make conversations on Facebook better, especially for posts with plenty of comments. Above a certain number of entries, a single-threaded comment column isn’t useful anymore. With the new reply system, smaller, compartmentalized conversations can happen.
Facebook is making Replies opt-in for now. However, as of July 10, all pages will have the feature enabled as well as all users with more than 10,000 followers. Facebook has been working on this for years, this latest version is a few months old. But it says that after a lot of experimentation, the feature is ready. In practice, it works as you’d expect. Users and page owners can reply to any of the comments in the main thread. Facebook also employs an algorithm to surface the most interesting conversations and push them to the top.