What would be best way to go about marketing a new online dating website?

A friend of mine is investing a lot of time, money, and resources into launching an online dating website. What would be the best way to launch the site? How best should it be marketed? Where and how should it be marketed online? What kind of offline marketing should be used? Anybody know anything about Ad Networks and how a site can generate revenue from them? Any help would be greatly appreciated. Thanks.
Thanks for all the answers so far!!