By having your friends be a measuring stick in search results publishers now need to target those friends in order to get a page in front of you, and so they will. Top rankings in search SHOULD involve content that can stand on its own but sadly this move brings us closer to a point where something other than quality decides what Joe and Jane doe see in serps.
Let the games begin, publishers everywhere devise ways of artificially increasing your circle of "friends", go!
This SHOULD be entirely separate from actual search results yet there it is, combined. Some of the best content online is old and will never get a "like" button and so it's doomed to fade away? That's a shame.