This has been around for a long time... it's the phone numbers that your friends on Facebook willingly submitted, they just make it easy for you to see whose phone number you already have access to through Facebook without having to go to someones profile.
The contacts listed on that page aren't even in my phonebook.
It seems like that page only lists the numbers from people who willingly shared their number if you canceled out of the import feature after installing the facebook app on your phone.
Not "if you use a mobile Facebook app", more like "If you said yes to some option that allows them to do this". I've had the Facebook app on all my phones the past few years (1 java, 5 android, 1 symbian), and yet I have no phone contacts here.
You're wrong, it's actually a copy of the contacts stored on your phone. On my account, the local pizza place and haircutters are listed, which definitively do not have facebook user profiles.
Only if you imported your contacts. That list was only my friends on Facebook who put their numbers on Facebook. Most of them are not in my address book.
