Why do I get these random friend requests from girls on facebook?

It's annoying I have no idea how they get my name and stuff. They are random girls I think they are some fake profiles. I looked at their wall and it had like links to pictures of them supposedly . I didn't click them because I think they where made like spam bots. One of the status updates is " T-shirt with my panties on....ooooweeeee" another is "@ prviate hi Josh here's my private picz I took of myself last night. you have to sign up for the p word a href="http://www.clcik-spicydtae-stie.com/5qc3"" rel="nofollow"http://www.clcik-spicydtae-stie.com/5qc3…/a What the heck... where do they get my information to friend request me.