Advertising spending on the Internet has soared. Indeed, by some accounts, Internet advertising is projected to reach $23.5 billion by 2005 (eMarketer, 2002). Although there are several ways of advertising on the Internet, for example, buttons, banners, paid links, superstitials, and so forth, banner advertising is the most common form of advertising on the Internet (Meland, 2000). Advertising using banners (usually placed near the top of a page) is currently the most popular form of online advertising. Banners may be static (stationary) or dynamic (rotating). In the case of static banners, all visitors to a particular site are exposed to the same banner. In contrast, dynamic banners describe cases where ad servers to a particular site deliver different banners to different clients/visitors. This approach presents the possibility of time/space sharing among different advertisers.