What is an ad network?

An ad network is a network or company that brings advertisers and publishers together. An ad network does this by offering and selling free advertising space from publishers on which advertising is to be placed to suitable advertisers.

Although there are also ad networks for TV advertising and print media, an ad network is primarily a network for online media. The advertising spaces in the ad network include emails, blogs, streams, websites and RSS feeds.

Ad networks are particularly important in search engine optimization (SEO) and therefore play a major role in online marketing. The best-known ad network is Google AdWords. Ad networks are also an element in search engine advertising (SEA), which influences the ranking of pages in search engines.