In other words, Facebook is trying to remove some of the spam from your iOS Contacts app by no longer syncing friends that have no useful contact information. According to a Facebook spokesperson, friends that have no contact information on their profile other than a @facebook.com email address will not be synced to the Contacts address book going forward.
The result, of course, is you might notice more than a few of your Facebook friends disappearing from Contacts. You can always add them back manually, but Facebook is thinking the majority of users will be happy with its decision to declutter its iOS sync feature. expand full story