Facebook has decided (without asking you) that developers of Facebook apps will now be allowed to harvest your personal contact information. Yes, that's as bad as it sounds. Actually, it's even worse if you understand what can be done with this kind of information in the hands of criminals or malicious people.
Basically, anything you post to Facebook or to any Facebook app will now be sold to the highest bidder. Your name, home address, and cellphone number are just the tip of the iceberg. Here's the personal information Facebook is selling:
"Birthdays, Religious and political views, Family members and relationship statuses, Significant others and relationship details, Home towns, Current locations, Likes, music, TV, movies, books, quotes, Activities, Interests, Education history, Work history, Online presence, Websites, Groups, Events, Notes, Photos, Videos, Photos and videos of them, 'About me' details and Facebook statuses"
In other words, "everything". Every single thing you've ever posted to Facebook, or ever will post to Facebook is now for sale.
Malicious app developers will now have lots of easy ways to gather even more personal information for criminal purposes, with you as the target. And it's all being done with Facebook's cooperation. Why this isn't classified as a crime is kind of puzzling.
For example, it will now be child's play to create an app that collects mobile phone numbers for the purposes of SMS spamming or for sale to telemarketers. Or better yet, why not use the collected phone numbers to sign people up for a premium rate service?
In a similar vein, phone support for most companies only ask for a phone number, address and DOB to "confirm" your "identity" before making changes to service plans or to release information about the account holder. Right. Guess what happens next?
It's probably too late, but we'd advise everyone with a Facebook account to immediately either delete all their personal information or change it to bogus data. For example, change your home and mobile phone numbers on Facebook to "650-543-4800". (That's Facebook's Customer Service number, by the way.)
Why is it probably too late? Because if Facebook will share your current data, they'll probably also share their backup data as well. In other words, one of the new items for sale will likely be the "information in user accounts before the last change".
Seriously, if you have a Facebook account, close it now.