You probably see Google AdSense ads all the time, but never realized it. How many times have you seen the words “Ads by Gooooooogle?” If you haven’t yet realized, I’ve added those very ads to this page!
Google is well known for their unintrusive ads, which are often helpful, and not at all annoying. AdSense scans the page you’re reading and delivers relevant ads that offer related pages. In this way, it is an easy way for web publishers to provide more content to the users while earning a bit of money themselves.
To see this in action, notice that if you browse to an article on this blog, the ads will change depending on the content on that page. If it is unable to provide useful links, it displays a Public Service Ad instead. Neat, isn’t it?