In its latest push into Web marketing, Microsoft on Thursday said it had acquired AdECN, an online hub on which Internet ad space is bought and sold at near lightspeed.

AdECN conducts real-time Web auctions for Internet ad space that are triggered when an individual surfs onto a page owned by an AdECN member. The system instantaneously culls demographic data about the individual, which is factored into bidding that is carried out based on members' predefined criteria. AdECN says its auctions begin and end -- and ads are displayed -- within 12 milliseconds.

AdECN's roster of participating agencies includes AMS Global Online, A Simple Internet, and Sierra Group Marketing. The company was founded in 2003 by marketing and digital publishing veteran William Urschel. Financial terms of the transaction between Microsoft and AdECN weren't disclosed.

The deal is the latest step in Microsoft's campaign to become a major player in the digital advertising market.

On Wednesday, the company announced deals under which it will serve up ads to visitors on the Web 2.0 news site Digg and place electronic ads in sports video games published by Electronic Arts.

In May, Microsoft said it had acquired Screen Tonic SA, a European manufacturer of software designed to connect online advertisers with users of mobile phones and other digital devices. Earlier this month, Microsoft announced a partnership with Ask.com under which customers of Microsoft's paid search program will see their listings appear on sites operated by Ask.com and its partners.

Microsoft also is expected to launch a Web analytics product that is currently in development under the code name Gatineau.