Does online advertising belong on the media plan? In 1998 the answer was certainly yes, but to what extent? This issue is of increasing importance as clients are very well aware that traditional media are not as good as they used to be at reaching large audiences. With increased media fragmentation and the range and sophistication of online media, the latter has become more interesting for advertisers. This has forced media agencies to confront the challenge of integrating the Internet into the traditional media mix. As audiences migrate, media plans follow, acknowledging that the ultimate goal of any brand is to reach its target audience where they are consuming media. This paper highlights the current Internet advertising marketplace, and pinpoints targeting opportunities for advertisers within this dynamic medium.