Depends on niche, recurring or new visitors, blended ads... A CTR = 2% will be great for a forum with many recurring visitors, but will be a poor CTR for another sites.
Usually anything between 2-4 CTR is normal for the average internet user. I never stop tweaking and optimizing my design and adsense units until I achieve around 10% or more. You can't do that with forums and webmaster sites though.
It depends on people. Some people go yoyo over 5% CTR and some people think 10% isnt good enuff. There is no limit to what CTR you can achieve as long as its legal
It also depends on how much of your website is return visitors. I have a ton of repeat visitors, so my CTR keeps going down. That's why I started up with CPM.
I feel the normal range is between 5 and 10. Of course, it differs depending on the niche, ad placement, nature of visitors and traffic load
The average is pretty low, but that's because the average is made up of a lot of sites that don't have good content, don't have well placed ads, and don't have ads that are relevant to the interests of site visitors. Of the sites that have good content, are not forums or blogs, have relevant ads, the average CTR can easily be 20%-50%.
Is not easy to get a 50% CTR. From my own experience is easier to get higher CTR with incomplete content than with complete content. Why ? Because your visitors could click on ads trying to reach the content not found on your site.
Totally agree - the site with the highest clickthrough rates are the 1 pagers with 80% of the screen taken up by ads and the user has nothing else to do but click on an ad to find something. An example (that was for sale a while and was claiming 33% clickthrough) is http://www.daronjones.com
Sorry but i dont agree with it. In fact having a good traffic website (plus 2000 uniques/day) i think if i had 20-50% CTR i´d warn google saying i was being clicked-bombed. It´s not natural those rates, even with very good ad placement, very well blended add and even niche oriented traffic and oriented adds it´s almost impossible to have those rates naturally. And i´m talking about 1month average at least. In fact i imagine those ctr rates associated with a good volume of traffic (+2000uniques) it´s a reasonable amount of money per day and would ring some bells in google offices.