Many banner ads are delivered by a central ad server.Banner ads can use rich media to incorporate video, audio, animations, buttons, forms, or other interactive elements using Java applets, HTML5, Adobe Flash, and other programs. The colloquial usage of "banner ads" often refers to traditional frame ads.Website publishers incorporate frame ads by setting aside a particular space on the web page.The Interactive Advertising Bureau's Ad Unit Guidelines proposes standardized pixel dimensions for ad units.
Like other advertising media, online advertising frequently involves both a publisher, who integrates advertisements into its online content, and an advertiser, who provides the advertisements to be displayed on the publisher's content.
Many common online advertising practices are controversial and increasingly subject to regulation.
Online ad revenues may not adequately replace other publishers' revenue streams.
Display advertising conveys its advertising message visually using text, logos, animations, videos, photographs, or other graphics.
Display advertisers frequently target users with particular traits to increase the ads' effect.