xxxblackbook is like so many of the other dating sites. Lots of fake profiles. It's also very popular with the people who are running scams on craigslist and social sites. That said, I read where people really do meet through some of these sites. Just be cautious, and read their terms of service closely or you may take a huge hit on your credit card.
Now swingers sites are a little different. Most are very legit. It's a lifestyle and they take it very serious. While xxxblackbook, adultfriendfinder and a few others claim to be for swingers, you have to go to sites like www.swingerslifestyle.com to find real swingers without of all of the fake ads. Plus, real swingers sites don't cost a fortune.
When will folks ever learn. There just aren't many real women, especially beautiful women, having to advertise for dates and to get laid. The only real sites I have found are swingers sites like http://localswingersads.com. The members aren't all really pretty and fit, but at least they are real.