The More the Merrier
Here’s a tip that’s really common sense. The more ads you have on a page, the more likely that at least one of those ads will be clicked. That is, the more things that can be clicked, the more things that will be clicked.
What does this mean, exactly? In the case of a web page, it may mean creating two or three different ad blocks. Maybe you put one block in the left sidebar, another just above your main content, and a third link unit at the bottom of the page. Heck, maybe you add another ad unit just below the core content, just for the heck of it. The key is that you offer multiple click points for the page’s readers.
In the case of a blog, you have even more options. First, you need to put at least one ad unit in the blog’s sidebar. Next, put a link unit at the bottom of the blog. Then insert ads between each and every blog post. The more readers scroll, the more ads they’ll see. (And these ads don’t interrupt individual poststhey just break up the flow between posts.)
So increasing the number of ads on a page worksto a point. If you end up with more ad space than you do true content, then you’ve gone too far. You don’t want people to think your site is all advertising, or they won’t come back. The content has to remain supreme, supplemented by the AdSense ads. This also means not having these ads be the first thing that visitors see; content has to come first.
I’ll give you an example of ad overkill. There’s a particular forum I like to go to for information about aquariums. The forum has great info, but at the top of every single forum page are four vertical blocks of ads, side by sidesixteen ads total, taking up the entire top half of the page. I have to hit the page down button before I see the first line of content. That’s too much; the ads are intrusive and make the real content appear secondary. This site would have done much better to drop all the ad blocks at the top and replace them with ads between every few poststhe same number of ads, but placed subsidiary to the core content.