An ad server is a computer server, specifically a web server that stores advertisements used in online marketing and delivers them to website visitors. 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 the name for the organization, hardware, and software that deliver advertising creative to the userâ„¢s browser. An ad server solution is a powerful online ad serving technology solution for publishers, online retailers, and other media properties.