POF has a new metric that some other marketing platforms could use and that is now you can target people that have previously converted. Not sure how they know if an advertiser converted from an ad, but it's a nice option to not waste time and money on worthless impressions. http://blog.ads.pof.com/2012/10/25/we-revolutionize-the-game-again/
that's interesting. I've been thinking quite a bit about this technology. glad to see it arriving.
POF gives you a tracking pixel to place on your conversion page, so that's how they track converted. Good data to have if you're POF