Who should fear Microsoft's lawyers most?

Welcome to the "Linux Everywhere" world. Microsoft now loves Linux, even if Steve Ballmer wouldn't don a penguin suit.
Yes, Linux, I think we can safely say, has won. Oracle wants to get it to you cheap. Microsoft wants to let you choose how to deploy your applications -- on Linux or Windows instances, perhaps on the same machine or blade rack. Intel, AMD, Dell, HP, IBM, Sun -- they all just love Linux.
Linux has never been in better shape, as long as Microsoft doesn't think you're abusing their intellectual property. Microsoft today with its Novell agreements is essentially offering Linux indemnification when Windows and Linux play together. But you will pay for it. Want to be safe using Linux and Windows together? Better buy SuSe support from Novell. That's the message.
Of course, Oracle is also offering indemnification. So is Sun. IBM and HP seem to, too. So what gives? Is Microsoft making idle threats? Will they back the threats up by suing their own customers? Will they sue big customers? ISVs? They will need a whipping boy, or the implied threat is a bluff. The SCO thing didn't really work out. No fear there.
SCO or no-SCO, Microsoft needs a Linux-Windows TCO story that makes legal risk the difference between SuSe Linux TCO (with a Windows mingle) and the TCO of the rest of Linux (with a Windows mingle). And what's the big difference here from yesterday? It used to be a FUD threat of Microsoft, or proxy, bringing on legal wrangles if ANY Linux were used. Now, it's only non-SuSe Linux that might peeve Microsoft's lawyers.
As the Peggy Lee song says: "Is that all there is?"
Tactically, this was not the really big show that the lead-up to the announcement suggested. For those shops really worried about getting sued by Microsoft, they ought to go SuSe. Fine. Still, I'd say that the threat is mostly hollow. And I'll stay with that position until Microsoft sues a Fortune 500 company for intellectual property transgressions, which will just push enterprises into a pure Linux play.
But strategically there is a big, big story here. Microsoft just said "uncle" on Linux. They had to save face, so they did it behind a smoke screen of indemnification malarky. The bigger story is that the software game has changed to one of a battle between the "friends of Linux."
In other words, it's now a world of "our stuff" plus Linux against "your stuff" plus Linux. Microsoft knew that virtualization and SOA were going to make moot most distinctions between applications/services supported by a Linux kernel or a Windows instance. They saw that developers increasingly prefer to build, test, and deploy on open source ... and then let someone else worry about porting to Windows, if necessary. This is especially true for SaaS and service provider ISVs -- where cost is super critical.

I do think the timing on this is curious, and had to have something to do with Oracle's Linux move.

In any event, now that Microsoft loves Linux, too, the open source vs. commercial battle moves up the stack. Yes, it's clearly a stack world now, and the next battle ground is ... middleware. Linux is a must-have commodity within any stack -- a Windows stack, an Oracle stack, an IBM stack. You name it. Microsoft says so.
The real end-game for open source then is the rest of the stack, right up to and including the business applications. The new questions are: Will the JBoss model be repeatable and allow Red Hat to successfully move up the stack? Can they do it without IBM and Oracle? Will SOA emerge as a strong open source alternative? Will the hardware providers begin to give away the software, ala Sun, to pressure the non-hardware software players on price and make the profit from the hardware alone? Will the SaaS providers squeeze the business applications profits even as the profits in the Linux bottom of the stack wither?
Even as these questions are resolved, the ISVs and the enterprise developers now know: Design, build, and deploy on Linux, and have low risk, low cost. And may the best services within the rest of competing stacks win -- on both quality and TCO, be they commercial, open source, or commercial open source.
Oh, one more thing ... Should we expect Microsoft to also soon offer indemnification protection when one mingles Windows with Unix?