Google generates revenue mainly through advertising on the search engine. Advertisers provide ads to Google that contain lists of keywords relating to their product or service. When a user searches something on Google and use one or more of those keywords – an ad appears on the results page. The advertiser pays Google every time a user clicks on the ad and is redirected to the advertiser’s site.

Another method of ad revenue Google uses is AdSense. Instead of display ads on the results page, the ads are integrated onto a participating websites page. An AdCrawler, also known as a spider/bot, uses analytics to display relevant ads to the user.