An ad network (advertising network) is an intermediary company that acts as a broker between advertisers who want to purchase inventory and publishers who want to host ads. Publishers, in this context are typically website owners, although they may also be app developers.
Ad networks acquire inventory from multiple publishers and segment the data based on details about the sites or applications and their audiences. Those details typically include demographic data, like age groups and geographic locations, as well as other areas that enable targeting, such as gender and interests. The ad network sells the data at a profit based on the added value of segmentation that enables more targeted advertising, which is more effective and profitable.
There are a number of types of ad networks, in several categories. A vertical ad network may offer advertising across a particular channel, such as sports, or may be specific to a website, similarly to the traditional model in which publishers sell directly to advertisers. Blind ad networks offer the lowest pricing to advertisers but also the least control in terms of where an ad will appear. Targeted ad networks enable targeted advertising by accessing consumer data stored in an ad server.