Facebook has announced that from Monday (25 March) anyone with more than 10k fans on their Facebook Page will be able to opt in to the social network’s new replies and most-active threads features. The former enables people (including Page owners) to reply directly to comments made on Facebook posts, with those replies appearing as threaded conversations. The latter sorts the responses to a post by pushing the most active threads to the top, which in theory (and we stress the ‘theory’ part of that) will help the best conversations bubble to the top – appearing differently to each user depending on which threads their friends are commenting in, if any. According to TechCrunch, the feature will be opt-in for now, before launching across every Page in July. One not-so-good aspect to this, though, is that replies and threads won’t work for now in Facebook’s mobile apps and site – mobile users will simply see them as normal comments. Given the heavy usage of Facebook on mobile, and CEO Mark Zuckerberg’s recent insistence that “Facebook is a mobile company”, this is puzzling.