It seems like everybody and their grandfather is on Facebook these days. One way to know for sure is by using one of a few applications Facebook offers to keep track of your relatives. Applications like FamilyLink (formerly called “We’re Related”) and Family Tree are a good way of noting who you’re related to and how. Even your friends can see your Facebook family tree.
But I’m not sure how useful this is since that’s pretty much all you can do. Sure, you can see how far your tree currently branches but ultimately we’re all cousins and who really cares if you’re 23rd cousins twice-removed with someone in Bangladesh? (I’m sorry, cousin Ahmed. I didn’t mean that. Please don’t un-friend me!)