I've got the iPad 1, and at least once per session on FB, safari will shut down and return to home screen. I have to start safari again and log back into FB. I am using the FB website, not the app. It will do this with some other websites, but it is consistent with FB. I am on the latest iOS - 5.something. My daughter's iPad 2 doesn't seem to have this problem, but she doesn't let me use it very often to truly know....