>Advertising that gives back

From an end users perspective, there won't be any difference to normal advertising. Unless they know that the money is being donated to charity it will make no difference to them.

I think the core of the idea is great and anything to help charity should be promoted as much as possible, but if you're not making anything from the ad impressions how do you plan to fund your infastructure, staff and other things you need to run successfully?