Are having less ads, such as here on DP, better for a low ctr? If you have the maximum number of ad units, but a relatively low ctr, are you better off with just one ad unit?
It depend on the site if you have max units but very less content you are likely to get smart priced so your cpc will get lower if you have more content max number of units are welcome
Your CTR might increase but not the number of clicks, I guess you know the calculation of CTR. If you need more clicks then highest number of ad blocks are must.
There is a huge chance of a site visitor clicking an ad in a site with less ads. With many ads, there would be too much competition for attention.
all you need is 2-3 ad units well positioned. using lot of ad units means you are serving lot of ads and more ads you serve, better chance for you to get low paying ads being displayed on your site. you don;t want your visitor to click on low paying ads therefore less is more.