they're all part of Spring Street Networks, the personals service that spun off of Nerve.com (Salon Personals is part of this network too).
Yeah, it's Spring Street. Filmstew.com and HighTimes.com (the first is a film industry insider site, the second...if you don't know, let's leave well enough alone) also have it. They get new sites to do it all the time - but it's so crowded with people from crappy sites it's hardly worth it now.
Is anybody making money with that deal?