It's curious. Lots of people I know use okcupid; nobody I know uses PoF. The one time I tried joining several years ago, my account was repeatedly deleted. PoF has a target audience, but I have no idea what or where it is. Does anybody?
For those who say PoF is an inferior product: with dating sites, it all boils down to 1) number of local users, 2) easy results filtering, 3) easy communication. For me PoF had all three.
I met my wife on PoF, by the way, so: Thanks!
http://trends.google.com/trends?q=okcupid%2C+plentyoffish...