Good point - though they did eliminate the brand with Beluga, and they probably won't with Instagram. That could change though.
Besides messaging and photos, I'm thinking that few things are left as halo products around Facebook. There's no reason for a "games" app - to me, at least - but there might be logic in acquiring something like Turntable.fm for music.
I like this thread of reasoning. Also ties into the whole "Facebook" phone. If they were to build one, it's possible it would be android based so maybe that's why they were just waiting for the android app. I was thinking Spotify for the music given all the ties to FB, but may be too big now.
