My expirement detailed in this thread seems to validate my assertion that redirecting SU back to itself, seems to have a positive effect on eCPM. All other factors in terms of traffic remain the same. It is a fact that SU visitors are not good for the advertisers, getting rid of them increases the mix of good traffic.
When you say redirecting it back to itself, do you mean you are redirecting SU traffic back to the homepage stumbleupon.com?
yes -- add this code below to your htaccess file, and it will just redirect the user back to SU main page: Options +FollowSymLinks RewriteEngine on RewriteCond %{http_referer} ^http://([^.]+\.)*(stumbleupon)\.com RewriteRule .* http://stumbleupon.com [R=302,L] I mean, there might be arguably some other benefits to SU traffic like overall exposure, but this might be an option for some. I found no real use for bored, untargeted SU visitors. I was also getting a lot of "discounted clicks" too (G said they discount "curiosity clicks")