I've got 6 right now. I used to have 3 adsense ad's scattered between blog posts and 3 YPN ads on the sidebar. Since reading this forum, I learned that adsense and YPN can't be on the same page so I switched adsense over to YPN. I can't find a suitable alternative to adsense or YPN in revenue. Any ideas? I tried Adbrite, Kanoodle but nothing comes close to either adsense or YPN.