Facebook Mobile harvests entire address books, leaves soiled contact lists in its wake

While it's by no means a new feature, people are starting to notice what Facebook Mobile's Contact Sync actually does, and it's not pretty. At the very least, it will trash your phone's address book by overwriting it with Facebook contact info and profile pictures. More disturbingly, while it's doing that it sends your phone's entire address book to Facebook, to be hashed and badly matched up with information gathered from other users' profiles and address books.

The feature has been around since January of this year, but it's changed over time. At first, and this was only dealing with iPhones at the time, it would replace contact pictures but it didn't write phone numbers or email addresses to the phone's address book. It did, as Kurt Von Moos pointed out back in February, grab your entire address book and send it back to Facebook servers. That changed over time, and today it freely ravages your iPhone's contacts, while still gathering as much data as it can.

The only saving grace, for the iPhone at least, has been that users actually have to turn the feature on in order for the app to do any of this. Unfortunately, it never warns users that it's going to use their address book for Facebook's purposes.

The problem isn't isolated to the iPhone app, either. Facebook for Android has the same feature, and BlackBerry is even worse.

I had an ireful experience not too long ago when I realized that the BlackBerry version of Facebook Mobile installs with an opt-out approach to the feature, instead of simply having the user turn it on later. I use Google sync for my contacts, and I was none to happy to find that many of the entries in my Google Contacts had been overwritten or cluttered with duplicate contact numbers by Facebook. All the pictures I had for my contacts were ruined as well, having been replaced with extremely poor-quality Facebook profile pictures, which also had little blue Facebook tags on every single one of them.

While messing up contact lists is massively annoying (I was so put off by seeing tiny blue dots on all my contacts that I wiped the whole list and started from scratch), the most disturbing thing going here is the use of your phone's already extant address book contacts during syncing. As Craig Scrogie told the Guardian in their post about this, Facebook had used contact information from his phone for a mechanic's garage, and matched it against a completely random user who happened to have a similar name.

According to Craig:

One example from my list (I've changed the names here to protect privacy): On my phone contacts I have "Steve Car" -- my mechanic. On my Facebook Phonebook this is shown as "Steve Carlton" who I don't know, and it shows his mobile number (different to Steve Car).

Craig saw the user listed in his Facebook Phonebook (see yours here). He also noted that the user he calls Steve Carlton has his profile set to private, yet Craig could still see his phone number.

Phone numbers on Facebook going more public than intended may sound familiar if you've seen Tom Scott's page of Evil, but this is entirely different. Evil scrapes search info from Facebook posts about lost phones, that people inadvertently mark visible to "Everyone." If you post your phone number in a thread that's visible to the entire Internet, you really have no room to complain in the first place. Facebook Phonebook suddenly showing your face and phone number to complete strangers, on the other hand, is a problem.

If a user wants to allow Facebook to muddle up his phone's address book with piss-poor images and bad phone numbers, that's his business, but something is clearly wrong when it comes to Facebook harvesting the contact data from users' mobile phones. Phone numbers aren't exactly the most closely guarded personal secrets of our generation, but people don't generally expect them to be snatched from their phones and put through Facebook's Slap-Chop database system, either.

Tags: Android, BlackBerry, facebook, iPhone, mobile apps, MobileApps, news, phone numbers, PhoneNumbers, privacy, social networking, SocialNetworking