If you give it your email address’s contact list, it will pull up the majority of the contact list’s members from their profiles on major social networking and media sharing sites.

I was given an e-mail invite from someone, and was surprised by how Spokeo immediately pulled up everything that the contact list’s inhabitants have done recently on all of these sites. Wikipedia has a list.

It’s fucking creepy, and one runs the risk of accidentally mass-spamming the entire contact list with invites. However, despite its shortcomings, it does have a good interface, and it does give a frighteningly-superb view of social networking profiles rolled up for easy pickings.