-By Brian Morrissey

NEW YORK Microsoft continued its effort to offer a complete set of tools to advertisers and publishers by inking a deal to purchase Rapt, a company that helps firms manage their ad inventories.

Rapt is used by several top Web publishers to manage ad-inventory sales. It forecasts how much a publisher can get for ad placements, and whether they should sell the spots themselves or use ad networks. The company works with publishers like CNET Networks, Dow Jones and The New York Times. Rapt also helps Microsoft manage inventory on its own sites.

Financial details of the acquisition were not disclosed.

The acquisition intensifies the growing competition between Google and Microsoft, as both seek to offer an array of tools (from ad serving, campaign management and ad exchanges and networks) to buyers and sellers of digital advertising. Google, of course, significantly bolstered its standing this week when it completed its acquisition of DoubleClick.

Rapt will become part of Microsoft's Atlas suite of services for publishers. The company has 85 employees and is led by Tom Chavez, who will join Microsoft.

"We have the best array of publisher assets and the smartest array of folks to help [publishers] pull the levers and turn the dials to make them more money," said Scott Howe, general manager of Microsoft's advertiser and publisher solutions group.

In the estimation of Google and Microsoft, publishers and advertisers will outsource much of the technology needed to manage their online advertising efforts, relying on the wide-ranging platforms the two companies are building. Howe said some publishers would offload nearly all of their operations to Microsoft, while others would only need pieces.

"The recipe is going to be different for every publisher," he said. "We want to give publishers an a la carte menu."

Microsoft hopes the acquisition will add momentum to its publisher tools business. Howe boasted that since Microsoft's acquisition of aQuantive it won 70 publisher clients, many at the expense of DoubleClick.

Rapt has also developed similar tools for agencies and advertisers. Last month, it inked a deal with Publicis for its agencies to use Rapt to make better decisions about ad pricing. Chavez said it would continue to focus on analytics and yield tools for both the buy and sell side of advertising.