Microsoft is adopting a soft-sell approach to fighting Linux and open source.

Microsoft CEO Steve Ballmer praised the transparency of open source on Thursday. "You can peek through the door if you can't figure out how something works," he said.

Earlier this week, Microsoft actually submitted some source code under an open source license. The company submitted WiX, or the Windows Installer XML, to SourceForge.net, a central clearinghouse for open source software. WiX is a tool used to allow developers to build installers for applications; Microsoft uses WiX in its installers for products including Office, SQLServer, and BizTalk Server.

The WiX open source submission was done under the auspices of Microsoft's Shared Source initiative, a program whereby Microsoft releases source code to selected customers and partners for them to examine, but not alter.

Jason Matusow, shared source manager for Microsoft, said in an interview with Linux Pipeline earlier this week, that the WiX release is part of a trend where open and proprietary software vendors are adopting pieces of each others' business models.

"There is a move to the middle," Matusow said. "There is a process that is happening away from the hardline points that you are either open or closed. I think that has gone completely gray at this point."

This soft-sell approach is a long way from a few years ago, when fire-breathing Microsoft executives, including Ballmer himself, compared open source to "cancer" and the open source community to Communists.

But Microsoft still wants you to buy its software, rather than open source.

Ballmer said Microsoft's approach to integrating applications and operating system leads to lower cost of ownership and less complexity, while not blocking users from using other vendors' technologies. And he said the open source development model, which allows "every Tom, Dick and Harry" to contribute, makes it hard to figure out whether other people's intellectual property are being wrongfully submitted to open source.

Matusow said opening WiX source code is part of of an effort by Microsoft to apply the open source process to its own business. He said many proprietary vendors are doing the same thing. Apple combined FreeBSD and its proprietary Macintosh operating system to create its current OS X. IBM aggressively supports Linux while continuing to have a $14 billion proprietary software business, including the DB2 database, and Tivoli systems management software.

Microsoft's own Shared Source program is designed mainly to allow developers to examine Microsoft source code for security and compatibility, Matusow said.

A year ago, a retiring high-level Microsoft developer criticized the company for failing to learn from the open source community. David Stutz posted an open letter to the Internet, saying Microsoft needs to adopt the best practices of open source while remaining proprietary software company.