I don't buy that people here met their GFs/EX via Facebook without at least some background. SANE Woman just don't creep on random men's Facebook going "Hey, can we talk?".
Men creeping on a Girl's Facebook however...
Yes, because it's absolutely "sane" to act prudely about things, to be the supernomal member of society that's playing hard to get and to end up not having kids before age 40 or, god forbid, 50 or even 60. Totally not the way mother nature has designed human beings.
That is until you realize that there is no barrier to prevent two consenting adults getting together and having some fun.
Anything that says otherwise is hogwash, a social construct designed to exacerbate sexual frustration and generate all sorts of commercial opportunities including those badly designed dating sites which are only interested in your money.
Think about it and let it take root.