Yahoo is planning to launch on Wednesday, August 3, 2005, its ad network for small Web publishers intended to compete against rival Google in text based ad. Google AdSense has been enjoying kind of monopoly in text based ad services since its launch, now Yahoo hopes to tap into the same ad territory.

In fact, Yahoo has been working on this self-serve advertising service tailored to bloggers and other small Web publishers for months before decided to launch it publicly.

Quoted:
Now Yahoo will play to that constituency and challenge Google’s pricing power in one of the fastest-growing online mediums: blogging. Like Google’s service, Yahoo’s self-serve product will display text ads deemed relevant to the content of specific Web pages. Advertisers pay only when a reader clicks on their ads. Yahoo and publishers will split the fees.

Source