Microsoft on Wednesday opened its PubCenter advertising service up for public beta testing, providing more of an alternative to Google's AdSense and Yahoo Publisher Network technology that places ads on publishers' sites.
All the services scrutinize the content on a Web site and place advertisements the service deems to be relevant to that content. As with ads on search sites, the advertiser pays only when a reader clicks on one of the ads, and revenue is shared with the publisher and the company operating the ad service.