I use facebook, I've not upgraded the app on my phone for ages though, some of the permissions it wants I wont let it have.
But when I was having a paranoid privacy day I did once remove it, boy did my phone not like that (HTC Desire C) I had to re-install the app to get it working again. :(
I don't remember specifics, and probably could have sorted it out without caving in, but
1. I rather liked having facebook
2. I needed my phone to work