Newspapers May Face Ad Difficulties on Web Sites, Too

Newspaper sites are the patent-leather stilettos of the online world: they get used for special occasions, but other shoes get much more daily wear. The beneficiaries of this behavior are networks and exchanges like Advertising.com from AOL and DoubleClick Ad Exchange from Google, which dominate the buying and selling of extra space.

At nonnewspaper sites like Yahoo and Google, revenue...