In my theme, I link all the articles in my sidebar. When a visitor arrives they read the article on the page they landed on (for whichever keyword) and most them of them browse around using those sidebar links since it's all related.
Earlier this week, i accidentally turned off my sidebar widget without realising it and the adsense CTR quadrupled. Unique visitors remained the same, but page views took a nose drive. But it's not bad trade for 4 times more earnings.
What do you guys do these cases? Do you leave plenty of navigation, or reduce navigation to improve CTR.