Whilst being a fan of Facebook I do take certain steps to secure myself against identity fraud. I don’t allow my profile to show my full birthday. My contact details are only available to friends who would have them anyway. However, I’m often surprised by people who are happy to post information such as their mobile phone numbers for all to see.
Try this as an example, log in to Facebook and search for “lost phone”. As of right now, this came up with 459 Groups in my networks. Click on the group tabs, and have a look at the groups. They are mostly people creating a group and posting “I’ve lost my phone and all my friends numbers, please write your number on the wall”. Nice idea, except that the group is open. So not only do I know that Megan Prosser dropped her phone down the toilet whilst looking for eyeliner, but I also have Tessa, Hermione, Tabitha, Isobel, Clare, Helen, Uri, Matt, Alice and Mark’s mobile phone number. And that was just the first group I clicked on out of 459!
Maybe Facebook should make groups closed for just your friends when you initially create them rather than open to all?