The bidding process in Google AdWords is based on an auction system. Advertisers set a maximum cost-per-click (CPC) bid for their ads or campaigns, based on the maximum amount they are willing to pay each time someone clicks on their ad. When a search query containing the targeted keywords is made, the Google AdWords system evaluates all eligible competing ads and their respective maximum bids, quality scores, and relevance, then displays the winning ads in a specific ad rank order.