Adsense Middlemen

The New York Times: Consider this somewhat strange development: search engines like Google and Yahoo have become so proficient at attracting advertising that even competitors, like newspapers and yellow pages publishers, are now selling ads on their behalf.
Newspapers like The Houston Chronicle, which is owned by the Hearst Corporation, and yellow pages publishers like the BellSouth Corporation and SBC Communications have recently turned themselves into de facto agents for the search engines in the small-business market, where the Internet companies have had limited success.
Businesses like yellow pages publishers, which exist solely to serve the local advertiser that Google and Yahoo covet, may appear to be cutting their own throats by passing those customers onto the search engines. But the publishers argue that they are taking advantage of the chance to make additional money, while also studying the search engines closely enough to determine a long-term strategy to compete with them.
Ad Agents for the Search Engines [The New York Times]