Why does FaceBook's "People You May Know" keep recommending strangers?

[Kim]

And I'm not talking about folks I have only one or two mutual friends with - I'm talking, like, never seen or heard of these people before in my entire life. Every time I look at my suggested FaceBook friends, I see these long lines of Indian, Tunisian, and Arab women, sometimes with a few dudes tossed in. I have only a few Indian friends, but none in common with any of these people. To give you an idea of how odd this is getting to be, I had this one extremely pretty Arab girl showing up as a suggested friend for a few weeks, even though she had only about 50 friends, none of whom I or anyone else I knew had added.

[abraXus]

they base those people on more than just mutual friends.... things like schools or cities in common... or things that you both like... it's not just mutual friends