Advertising permeates the World Wide Web, just as it pervades television, radio, public space, and print publications. However, the form, presentation, and content of web advertising can differ significantly from other types of ads. Compared with television and print media, web-based advertising can be media rich and far more interactive than any other type of advertising. Web ads are also more diverse than print, television, or radio ads. For example, web advertising ranges from simple sponsored text blurbs such as those contained in the sidebars of any Google search to animated banner and pop-up ads to Flash films complete with sound. Web ads also put the viewer closely in touch with the source vendor in a way that print, television, or radio ads cannot. With a web ad, the viewer can, and is even encouraged to, connect directly with the company website to make a purchase. Moreover, with the World Wide Web, ads can be targeted to individual viewers in ways that can never be done through less personalized media. However, in spite of such media richness, web advertising also has limitations not present with television and print ads. For example, marketing campaign continuity cannot be established with Web-based ads in the way that such continuity can be established on television or even in print. Still, web-based ads are a powerful marketing tool when used to its full potential.

             The most basic web ads are those that are in plain hypertext. Coded in HTML, these ads are effective insofar as they do not bombard the viewer with unwanted sounds or visual imagery and may therefore put off fewer people than a pop-up. On the other hand, because of their unobtrusive nature, hypertext ads such as those found on Google searches can be easily ignored. E-mail Spam can be included in the web ad category, for much of Spam is sent specifically to free web-based e-mail accounts like those sponsored by Yahoo and Hotmail.