I am thinking it is mostly a scam... they do put a lot of spammers on there to draw guys in. But with that said, I am sure some real females do sign up. It's just a matter of finding them.
Note: If you try it... do the free sign-up and then go to delete your account. When you do, there will be about 3 different offers to get lifetime membership. In the end, it is like a $9 one-time charge for lifetime.