I gave up on facebook when I figured out it was the devil's work. Or to put it another way, its all about Mark Zuckerberg and the coming world government's attempts to gain as much information about people as possible.
In the early days of facebook I did notice something about it regarding dating. I was easily able to find lots of girls on facebook I had casually met once or twice and noticed their relationship status of in a relationship with so and so. Then I would completely forget them. After a bit I started to think that there is something really stupid about it. Namely that where I live there has always been a sort of "don't ask, don't tell" rule about "boyfriends". A boyfriend is not the same as a husband and can mean any different length of time from one week of dating to 5 years or more and doesn't necessarily mean anything. The rule was always don't ask a girl directly if she has a boyfriend but talk to her and if she feels the need to tell you such, then move on, if not remember that women are like monkies, they won't let go of one vine until they have a hold of another.... so she might even have a boyfriend, but if she doesn't let you know, you're free to keep trying. Facebook changed this rule with girls making public announcements of such for all to see and placed boyfriends closer to husbands with a public record of such. Actually, my last checks of facebook seemed to suggest girls had more figured this out and were much less likely to put up their relationship status. But there was at least four or five girls I had met that gave no indication to me that they were anything but single who I never tried with because of their facebook accounts.