Scuttlebutt is the software you're looking for. Check out the patchwork client. Posts are public by default but you can make them encrypted so only your friends

Scuttlebutt is the software you're looking for. Check out the patchwork client. Posts are public by default but you can make them encrypted so only your friends can read them. There's also cabal chat which is based on the same underlying technology but is chat focused rather than Facebook like.