I only click when I find something intresting and even browse thru other ads. Like just a few days ago there was an offer of free godaddy card for posting a nice webhosting review. Couldn't use it though.
I clicked on one ad which was related to link building in last 3 months . So you can say thatwebmaster only click when they find any useful product for themselves .
This thread is against Adsense TOS. Even though the admins did not create this thread, they allow it to exist, and it encourages users to click the ads. I click the ads daily because I appreciate the service. I am a webmaster and wish everyone who viewed my site was like me when I view another site - I ALWAYS click the ads on sites, and I don't hope for the karma back, though it feels good to do it.