source from The system that makes Contributor work is the same auction system used by advertisers to run advertising on the web. Instead of bidding on behalf of an advertiser, Contributor bids on your behalf, with the budget you set up. The Google ad auction determines when a thank you message will appear in an ad space, and how much it will cost. In the ad auction, advertisers and Contributor bid for a given ad space in real time. Advertisers specify criteria that must be met, along with how much they are willing to pay to show an ad. An ad space might be more or less valuable to an advertiser depending on a number of factors, including what site it appears on, where a person is geographically located when they visit a page, even time of day. The maximum amount that Contributor bids on your behalf for a given ad space depends on a number of factors, including your remaining account balance for the month and the cost of the ad spaces where your thank you message has shown in the pa...