Fring and Privacy
I wouldn't trust Fring as far as I could throw their whole office building because they monitor your usage of the app all too closely. You have to supply them with your mobile number "to get an activation code" via SMS but when you uninstall the thing you start getting phone calls from them asking why you stopped using it and what you thought of it. If they're paying that much attention to how I'm using their software I really don't trust them not to be paying too much attention to what my IM usernames and passwords are as well.