IBM/Lotus Thursday hit back at Microsoft's boast that it plans to steal 5 million Notes customers this year by detailing a new 300,000-seat licensing deal with an Asian company and strong interest in Notes from emerging markets.

Last week, Microsoft's COO Kevin Turner told financial analysts that his goal is to have the company's messaging and collaboration software displace 5 million Notes seats this year. Turner also said Microsoft has replaced 8 million seats of Notes in the past two years.

It was another shot in a messaging and collaboration war that has been going on between the two for nearly 20 years. In the late 1990s, the two jousted using e-mail seat-count numbers that were often inflated if not outright dubious.

"It is very difficult to tell what Microsoft is talking about when they talk about numbers of seats or costs because they shove so much into their environment, but I do know we have been engaging against them and winning," says Bob Picciano, general manager of Lotus Software.

IBM/Lotus seems to be doing a better job of integrating current messaging and collaboration tools with next-generation tools like social networking.

In June at the Enterprise 2.0 conference, the two squared off on stage around social software (Lotus Connections vs. SharePoint) with IBM/Lotus showing its Connections tools as "the clear winner across the board," according to Mike Gotta, an analyst with the Burton Group who moderated the session. Gotta in his blog later chastised Microsoft, saying it "did a poor job of showing and explaining why business and/or technical decision-makers should consider SharePoint as a credible solution to meet the social computing needs of an organization."

A month later Microsoft's Turner lit into IBM/Lotus, which is now on the offensive and detailing what it calls strong fiscal second-quarter sales of Notes/Domino 8. The platform, which shipped a year ago, features a modular client architecture that can be customized as the front end for component-based applications.

The company says an Asian firm, which executives said would be named at a later date, will license 300,000 seats of Notes, as well as Lotus Symphony, IBM's open source suite of productivity applications.

IBM/Lotus says the deal is its largest ever in Asia.