SAN FRANCISCO » Instagram users could soon notice something different in their feeds: Instead of showing users the most recent posts first, the mobile photo-sharing app says it will give higher priority to posts that each user is likely to care about most.

If that sounds familiar, it’s because that’s how Facebook decides what to show users of its online social network. Facebook, which owns Instagram, has long used a complex formula to emphasize items it hopes will be “relevant” to each user, based on factors like whether the post came from a close friend or how the user responded to similar posts.

Instagram had previously acted more like rival Twitter, showing every post in reverse chronological order. But it says users were missing some older posts they might have wanted to see.