Even with thousands of curious people picking away at the file system, it’s always amazing how some things slip through the cracks for a relatively long period of time. Gunning For Safety was snooping around in iPhone OS 4.0’s file system and found multiple references to social media integration for the Contacts app. More specifically what as found was a .plist file for Facebook contacts. It would allow users to add their friends Facebook profile to their contact card just as they would their email address or AIM handle. What’s particularly special about the way Facebook integration is that they’re a “separate type of contact” meaning it’s entirely possible OS 4.0 will offer much more than a simple method for keeping details about one’s friends neatly organized. The Calendar app is also said to be able to interact with Facebook much in the same way. It’s too early to tell if these features will survive — for all we know all of these references could be dropped come the next beta and not resurface for a long time — but we’re really hoping their expanded upon and support is broadened out to things like Twitter and LinkedIn.