[HomeComputerGames]

I have read a study on this. #1 spot is great for fast traffic and branding but as said people are clicking the first ad because they are lazy.
The people that click lower down are the serious shoppers as they are actually reading the ads. Another factor is that people will often scroll to the bottom of the search returns and then once at the bottom glance to the right side of the screen. Since they are scrolled down, when they start scrolling back up you now appear towards the top. I hear middle placement has better ROI because of this.