According to a recent viral Facebook message, Facebook is collecting and giving out your's and your contacts' phone numbers. This is based on the fact that if you click on 'Contacts' (Account-Contacts) it shows you people that aren't your Facebook friends, but are contacts in your phone. When you download the Facebook mobile app and select to sync your phone contacts with your friends list, you can access all your phone's contacts on Facebook. The matching makes users uncomfortable because if a friend hasn't added his or her number on the social network, syncing your phone suddenly makes it look like they have. The feature also uses numbers in your phone to find potential Facebook friends.
Facebook's statement on your mobile privacy
Facebook made a statement on their wall saying that they're not sharing phone numbers. They say, “Our Contacts list, formerly called Phonebook, has existed for a long time. The phone numbers listed there were either added by your friends themselves and made visible to you, or you have previously synced your phone contacts with Facebook. Just like on your phone, only you can see these numbers.”
Despite their statement, users are still uncomfortable. Most of them would like the option to add the feature themselves without Facebook auto-adding it and users later having to uninstall. If you want to remove your mobile contacts from your Facebook page, click here.