A lot of people complain that with the algorithmic changes to the Facebook news feed, they don’t see what their friends are doing (which is all many of us want). In fact, those changes let to a tremendous amount of gaming the system. At first, Mark Zuckerberg denied anything was amiss, but over time, he has changed his tune.
Wired has a great article about the transformations that Facebook is undertaking to mitigate this problem. It’s a long read, but it is a very one.