More than 300 companies representing 2.8 million employees began migrating to Microsoft's collaboration and content management system in the last six months of 2007, Microsoft announced on Monday.

The number of users adopting Microsoft Outlook, Exchange Server and SharePoint Server is up 164 percent from the prior year, said Microsoft, which claimed many of them are former users of IBM's Lotus Notes/Domino communication and collaboration software from IBM.

New customers for Microsoft include Colliers International Property Consultants Inc., Westinghouse Electric, Coinstar and Siemens.

IBM did not respond to a request for comment.

Microsoft also said that its free suite of tools for helping companies migrate from Notes/Domino to Outlook/Exchange/SharePoint has been improved with features aimed at companies with hundreds of thousands of users.

For several years, Microsoft has offered free software to help companies and their IT consultants move employees off IBM's products its own.

Microsoft has tended to announce or release such software around Lotusphere for maximum competitive effect.

Outlook and Exchange pulled ahead of Notes and Domino more than half a decade ago.

About 101 million corporate mailboxes run Notes today. That should grow to 112 million by 2011, according to predictions from The Radicati Group Inc. But 304 million e-mail boxes will run Outlook and Exchange by that time, according to the analyst firm.

Microsoft is actively trying to accelerate that migration. Last year, Microsoft bundled those tools together for the first time into something it called the Microsoft Transporter Suite. That product focused on moving Lotus Domino 6 and 7 users to a system based around Windows Server 2003, Exchange Server 2007 and Windows SharePoint Services 3.0.

The primary improvement in the new version, according to Clint Patterson, a director in Microsoft's Unified Communications group, is the ability to divide the migration into batches of users or applications.

According to a white paper by Excipio Consulting, a firm that helps companies migrate from Lotus to Microsoft, the cost of migrating a 30,000-employee business would be US$6.6 million for all software, developers and extra support staffers. But, claimed the white paper's authors, that company should save between US$800,000 to US$1.5 million per year by using Microsoft software.

IBM isn't just sitting around. It offers its own free tools and guides for users interested in migrating from Outlook/Exchange to Notes/Domino.

It has also reinvigorated Notes with a belated modernization of the user interface in Notes 8, while also preparing the release of a free word processor called Symphony that will be tightly integrated with Notes and Domino.