As I pointed out last week there's a case to made for the proposition that Microsoft both should and will open source its next OS code base just as Sun is doing with Solaris, and for some of the same reasons.
In Microsoft's case, however, the weighting accorded those reasons is likely to be very different than it is for Sun. Thus Unix is inherently open - something Sun has recognised as important from the beginning and Microsoft undoubtedly views as an uncomfortable cost weighing heavily against adopting the BSD option for their new network OS.
Both companies would probably agree, however, that the ability to place license controls at the application level, rather than in the OS, is a major benefit since this allows them to get the OS into people's hands without incurring the PR nightmare that goes with enforcement efforts like Windows Genuine [dis]Advantage - or the PR risk associated with offering radically different business terms in the Asian marketplace.
The biggest single potential beneficiary from this kind of thinking is, however, neither Sun nor Microsoft, but IBM.
Let me posit a scenario:
This wouldn't have much direct impact on the Linux code base since, according to IBM's supporters there's no value there and according to SCO most of the ideas in the AT&T source have already been incorporated into Linux.
The business effect, however would be to place IBM in the same position, relative to Linux, as Sun is in relative to Solaris - in other words at the center of a community to which it could then apply some variation of Sun's Community License.
That would let IBM make Linux genuinely free again - while allowing it to build community by investing shareholder dollars in desktop and server variants ranging from today's x86 stuff to versions deeply optimized for cell and other PPC variants.
Most importantly it could apply the so called "business model" ideas developed by Red Hat, Sun, and others for applications licensing and paid support to its own services inventory - offering free Linux licenses that come with options for however many IBM consultants the customer wants on his premises for however long the customer wants to pay them.