deadsea - 11:00 am on Oct 18, 2011 (gmt 0)

My theory is that if you get some +1 from installing the button on your own site, it will have little or no effect.

On the other hand, when Google shows the +1 button next to your site in the SERPs, the rate at which it gets +1 would probably be just as important as CTR from Google's perspective.