Get Your Message Accross.
Get Your Adverts on Targeted Websites.
Only Pay Per Click.
If a website has a high volume of traffic, they can monetise it by selling advertising space on their site for this purpose. It then gives Google permission to show ads in these vacant spaces. Advertisers can get their adverts to appear in these spaces by using Google's Advertising tool which is called AdWords and using the GDN (Google Display Network option). The advertiser only pays when a user clicks on their advert. The advertiser is then charged a cost per click while the publisher sites (the website where the ad is appearing) and Google divide the revenue.
The vast majority of websites that sell advertising use Google AdSense. Opposite is a sample of the U.K. sites using the network.
Different targeting options are open to advertisers so they can select the types of sites and apps on which their adverts will appear. A very granular approach can be one option (shown below) by choosing the exact websites where they want their adverts shown. The alternative is to use one of Google's other targeting options such as keyword targeting for example on pages that have the words "internet marketing".