Norton Internet Security and Firewall are blocking most affiliate links & banners and even AdWords and AdSense ads. It may even be blocking your own site logo if it is a certain image size.
FYI - When I say "blocked" I mean erased, wiped out and invisible. It leaves a blank white spot where the banner or link should have been, making it look like your site is messed up or you are missing information.
With AdWords and Adsense ads the body copy is visible but the link is missing so you cannot click.
See example here:
http://www.5staraffiliateprograms.co...s-revenue.html
I have been researching this issue for awhile now, but just finally downloaded the software to start testing. I'm APPALLED and ENRAGED at how this software DEFACES websites and can effect webmaster/affiliate revenue!
See my full post at the Affiliate Forum:
http://www.webproworld.com/viewtopic.php?p=66855#66855
(Sorry for the cross post, but I thought the AdSense people would want to know.)