Jenstar - 5:33 am on Nov 6, 2005 (gmt 0)

The advertiser may have geotargeted the ads. So this might mean a click from the US is max valued at $1, a click from Canada has a max of $0.50 while a click from UK is max of $0.25. So a click on the same ad could produce a great variety in earnings simply dependent on where the visitor who clicked is located.

Don't forget advertisers can change their bidding at any time. So they could decide to have a max of $1 in the morning but drop it down to $0.50 in the evening. Or change it to $0.50 for the weekends.