Ad serving describes the technology and service that places advertisements on web sites. Ad serving technology companies provide software to web sites and advertisers to serve ads, count them, choose the ads that will make the website or advertiser most money, and monitor progress of different advertising campaigns.
An ad server is a computer server, specifically a web server, that stores advertisements used in online marketing and delivers them to website visitors.
The content of the webserver is constantly updated so that the website or webpage on which the ads are displayed contains new advertisements -- e.g., banners (static images/animations) or text -- when the site or page is visited or refreshed by a user.
In addition, the adserver also performs various other tasks like counting the number of impressions/clicks for an ad campaign and report generation, which helps in determining the ROI for an advertiser on a particular website.
Ad servers come in two flavors: local ad servers and third-party or remote ad servers. Local ad servers are typically run by a single publisher and serve ads to that publisher's domains, allowing fine-grained creative, formatting, and content control by that publisher. Remote ad servers can serve ads across domains owned by multiple publishers. They deliver the ads from one central source so that advertisers and publishers can track the distribution of their online advertisements, and have one location for controlling the rotation and distribution of their advertisements across the web.
The local ad server was first developed and introduced by NetGravity in January 1996 for delivering online advertising at major publishing sites such as Yahoo and Pathfinder. The company was founded by Tom Shields and John Danner, and based in San Mateo, California. In 1998, the company went public on NASDAQ (NETG), and was purchased by DoubleClick in 1999. NetGravity AdServer was then renamed to DoubleClick Enterprise.
One of the first remote ad servers was developed and introduced by FocaLink Media Services in February 1996 for controlling online advertising or banner ads. The company was founded by Dave Zinman and Jason Strober, and based in Palo Alto, California. In 1998, the company changed its name to AdKnowledge, and was purchased by CMGI in 1999.
Another remote ad server was first developed and introduced by David Stein at Burst! Media in January 1996 for controlling online advertising or banner ads. The company was founded by Jarvis Coffin, David Stein and Bob Hanna, and based in Katonah, New York. In 2006, the company went public on the London Stock Exchange's Alternative Investment Market (BRST).