CEO Steve Ballmer rattled Microsoft's saber against Linux among Wall Street analysts last Thursday. It's clear that he means to make threatening noises, but what exactly is under threat? And doesn't talking about intellectual property but taking no action to defend it ultimately weaken your claimed rights?Every time I hear Steve Ballmer talk about Microsoft's intellectual property rights, I wonder what, exactly, does he mean? Does he claim some of Microsoft's code found its way into the Linux operating system? I doubt it, but I don't really know.

What I think he's saying is that Linux users will wake up one day to find Microsoft claiming some piece of open source code they use with Linux is suspect and they better watch out. All Microsoft has to do is assert itself in court and reduce the value of their Linux investments. The place it might conceive that it has the power to do so are those points where Linux interoperates with Windows.

On the other hand, actually going to court puts Microsoft on exposed ground where it hasn't fared too well in the past. It opens up a lot of Microsoft documents to snoopy lawyers and the press, whose noses Microsoft would rather not see deeply buried in its business. It's a little hard for me to see how all this saber rattling actually leads to a defense of claimed intellectual property rights.

So for the record, I'd like to ask, what is it in Linux that exercises the head of Microsoft? Is he talking about the operating system, or open source code typically included in a Linux distribution, such as Apache, MySQL, Samba, or Hibernate. If it's one of the latter, then it's time for Microsoft to put its cards on the table and say what its complaint is. That way, Microsoft customers can know where their exposure is, if they're using Linux with Windows. What Ballmer actually said was: "The deal that we announced at the end of last year with Novell I consider to be very important. It demonstrated clearly the value of intellectual property even in the open source world. I would not anticipate that we make a huge additional revenue stream from our Novell deal, but I do think it clearly establishes that open source is not free and open source will have to respect the intellectual property rights of others, just as any other competitor will." That, of course, follows up previously unexplained remarks on Microsoft intellectual property somewhere in the Linux distribution.

As the Microsoft/Novell deal was announced last November, Ballmer said: "This covenant does not apply to any other form of Linux than SuSE Linux."

A few days later, he told the Professional Association of SQL Server: "Anybody who's got Linux in their data center today sort of has an undisclosed balance sheet liability," according to information posted on the Seattle Post-Intelligencer's site.

So, what, specifically, is the problem? Let's get beyond the shadowy threats.