Didn't try them yet but their homepage @ doublelist.com is extremely basic with no images and no other distracting advertising which is surprising for a personal site. I guess it is how they get curious people to join.
DoubleList says they have over 3 million members in the United States. Lots of cities with lots of ads posted. If I had more time at the moment I would create a membership and actual view some of these posts to see if they looked real ... or not. (since you cannot view a post without a user account)
I assume it must cost money to post a personal ad.
Seems to have lots of ads for all types of relationships, straight, gay, couples, etc...
Might be worth a look...