I have contacts in my Contacts app who are also friends on Facebook. I know the integration messed at least one contact up. Instead of simply putting the information from Facebook in the contact entry, iOS created a whole new contact from the Facebook info and linked them together. Problem is, it caused Siri to pronounce the person's name wrong. The phonetic first name was colored in gray. I have since stopped allowing Contacts to access my Facebook account, but really, Apple? Really?