I'm self-aware enough to know that if I weren't single, I wouldn't use facebook at all. As with many things in life, facebook is attractive to women, and the men follow the women.
I think it's why facebook really rules. It's the most casual place to ask a girl for a cup of coffee. If you sms it's a lot closer to harassing. And you can assume that you find practically any girl on facebook that you have met.