Does somebody know how the "people you may know" algorithm in Facebook works?

[Tom]

A person that I actually do know from many years ago constantly pops up on top in that field. I have disabled any contact possibilities and friend requests on my account. Can it be that she has been visiting my profile frequently or is there other reasons?

[[TERMiNAL]]

place+friends+School+Work=mutual friends/poeple you might know
well you fed the system by the place you live(d), school you are going/went to and people you know might know that friend.
in my case i'm getting people you might know from friends who kept in touch with people from Elementary school. I'm now in collage and i can say i've been getting people that are from the same college.