A horizontal ad network is a network which generally has hundreds or thousands of sites on different topics.
Horizontal ad networks offer scale, reach and numerous targeting capabilities for advertisers. Some large international horizontal networks deliver several billions of ad impressions per day and have broad reach.
Ad buying on a horizontal network is generally done by Run of Network and is often a blind buy.
For publishers, horizontal networks are a complement of in house sales.
A horizontal network can offer choices of channels:
See also : vertical advertising network