IBM also unveiled the week of March 27 tools, resources and the names of more than 100 participating partners as part of "Migrate to Penguin," an extension of its Move2Lotus program and a response to an opposing program launched by Microsoft in January.

Both companies have much at stake as enterprises began moving from hodgepodge pieces of collaboration applications to platforms, and migration campaigns mean big wins and big losses for both software companies, said Erica Driver, a principal analyst at Forrester Research, in Cambridge, Mass.

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"It's all about keeping a balance for these two vendors," Driver said. "These are really big decisions for customers. You're not just talking about convincing an IT manager to swap out an e-mail server. This is an entire infrastructure change. A win for either is a big deal; a loss for either is a big deal."

In addition to the $20 rebate per seat, which is capped at 1,000 seats or $20,000, "Migrate to the Penguin," includes no-charge education and certification to bring partners up to speed on Lotus Notes and Domino 7 development skills, and a hosted proof-of-concept component that allows customers to try before they buy on a Domino server environment.

IBM has migrated nearly 3,000 customers from Microsoft Exchange and other e-mail and messaging platforms to Lotus Notes and Domino 7 in the two years since those programs launched. Linux-based e-mail and collaboration software market share has been growing at 200 percent a year, IBM said. Microsoft remains the market leader at 51 percent, according to research firm IDC, in Framingham, Mass.

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Microsoft's January migration offering included no incentive, but did include several migration tools, which could make it a more attractive offer, Driver said.

These tools include Microsoft Application Analyzer 2006 for Lotus Domino, to improve the process of analyzing a Notes/Domino application environment and provide a framework for making the transition; Microsoft Data Migrator 2006 for Lotus Domino, to allow organizations to migrate data from Lotus Domino template-based applications to Windows SharePoint Services Application Templates; and Messaging and Coexistence Tools to assist companies with the transition from Lotus Notes/Domino messaging to Microsoft Exchange Server.

Tom Hillebrand, chief operating officer at GreyDuck Technology in Minneapolis, a Lotus software consultant, said migration incentives and the other offerings matter less to a solution provider than vendors seem to believe.

"It only really matters that transition is the right one for the customer," he said. "No one is going to move a client to a system that doesn't work for an incentive, to find out they lost the customer down the road."

Lotus Notes/Domino is an attractive package to the SMB (small and midsize business), where getting diverse applications in a single piece of software is enticing to small shops, and to any customer who has Exchange operating in an otherwise Unix system.