From the article: Meeting friends-of-friends is the best way to find cool people, because liking is transitive AND because the low social distances force people to be on their best behavior. If I were looking to date friends-of-friends in particular, I think I'd just use facebook directly. Though more often then not, I've already met such friends-of-friends via common events.
Imagine this; by utilizing a particular dating service you would agree to A) make your Facebook profile open to the person you are mailing and B) If both parties are interested in each other (designated if both exchange message more than once) this fact is known on each other's Facebook walls and C) if you go out on a date with this person (both people making this known to the dating website) each person open up their profile to the other individual to let the other person write a review of the date on their public wall?