Plenty of Fish has added an option to advertise only to people who have or haven’t clicked on ads previously. To be more specific there are three categories that you can target by either including them or not including them.
So how can this be used to work with your campaigns. If you are using unique creatives you could include people that regularly clicked links. If you are using standard busty girl pictures you can target people that are new on the system (login count) and haven’t been exposed to ads yet.