One example I can think of is how the new FB 2.0+ API does not allow access to a user's friend list unless the FB app is listed as a game. The friends API will only show the user's FB friends who also use the app. Not being able to access a user's friend list takes away much of the value of the FB API (IMHO). Also the double standard that FB apps listed as games get to continue accessing user's full friend lists is not only weird, but a bit unfair (also IMHO).