Currently I am experimenting placing more than one ad unit on my blog. At this moment I have the large rectangle ad unit and a link unit. My questions are: Would placing more than one ad unit mean less cpc? Would placing more than one ad unit lead to higher ctr or a lower ctr? and Would it lead to a decrease or an increase in revenue? Answer those questions from your experience please .
Assuming visitors to your site click only one ad then more ads = less CPC = lower CTR However, if there are more ads on a page it is more likely that more visitors will be interested in them so a low CTR wont necessarily mean fewer clicks. I think. There's no harm in displaying all 3 of your ad units.