There have been several. A few other non-matchmaking dating sites have added matchmaking as a feature, as well. (There is a matchmaker.com dating site, but I'm not actually sure that it does matchmaking, and the site blasts me with an annoying javascript chat-bot as soon as I visit, so I'm not inclined to explore further....)
Fundamentally, the matchmaker idea doesn't solve the chicken-and-egg problem of dating -- you still need to have people on the site with whom to make matches. While you could try to match people with non-users, this is really just a dressed-up form of email invites, which most people have learned to tune out. It seems that in order to really crack the chicken/egg problem of a new dating site, one needs to provide a value that is independent of the dating problem itself.
Fundamentally, the matchmaker idea doesn't solve the chicken-and-egg problem of dating -- you still need to have people on the site with whom to make matches. While you could try to match people with non-users, this is really just a dressed-up form of email invites, which most people have learned to tune out. It seems that in order to really crack the chicken/egg problem of a new dating site, one needs to provide a value that is independent of the dating problem itself.