I tried signing up as a publisher for one of my sites but it said my site did not meet the requirements.. my site has PR2 do you know if i need a certain alexa or more backlinks? I know my alexa sucks but i havearound 2500 backlinks.
I got in with PR4 sites and very little traffic. This leads me to think PR is more important than anything else to them.
I was accepted with a PR 3 website with very little traffic. As CountryBoy says , I think PR is a deciding factor for them