good_seed - 10:36 am on Sep 19, 2004 (gmt 0)
I decided to give away the earnings of one my sites a couple months ago. It doesnt earn much each month, but when I said on my "about us" page that 100% of earnings is given to various charities my click through rate went through the roof.
I took the message off as I was afraid it would get my other sites in trouble and the click through rate is now back to normal.
It's definately an incentive for site visitors.