I think Surfn has the best policy here.... no exit links.
But everytime I promise myself not to use an exit link, I find that at the very last minute I have an overwhelming desire to add one to Google's home page. In the false hope that Googlebot will look upon my site in a more favourable light.
But if I had a load of existing traffic from exits....... I would use mild scare tactics and develop a page which is an online guide to safe surfing. Because anyone hitting this from a porn site will be doing so because they don't wanna see porn (or at least not wanna see porn on the PC they are currently using).
Everyone who hits this site will have one thing in common..... being online.
Tell 'em simply how to clear their cache, explain the risks of surfing without a firewall, frighten them about data miners, the holes in XP & 98, port scanners, distributed denial of service attacks, trojans, personal privacy, etc............
Once you have enlightened them as to the risks they face and how guilty they should be for ending up at a porn site warning page in the first place, then they should be open to at least considering buying something to cleanse their online sins.
