That has been the proven way to monetize a patent portfolio, but is ineffective with open source. The general public license won't allow vendors to pay intellectual property licensing fees that are exclusive to their users. Even if a vendor would want to pay Microsoft, it couldn't.

That leaves two options. Microsoft is out to kill open source, or Microsoft will collect license fees from individual users.

The first option is popular with conspiracy theorists, but won't get Microsoft very far. The SCO case has demonstrated that going after open source will result in a huge public relations back-lash. In SCO's case, the legal battle has undermined the firm's core business.

The second option will make both Microsoft and enterprise IT users happy. Microsoft gets to collect license fees and enterprises can rest assured about their legal future. SCO has actually traveled this road with its "Linux licenses".

SCO can be dismissed as a bully that is lacking any substance, but Microsoft has a much better chance at instating a Linux tax. The company has already succeeded at doing so through its partnership with Novell, through which Novell will pay for each copy of Linxu that it sells.

As customers are signing up for Novell's Suse Linux, they are setting a precedent for paying the Microsoft Linux tax. And just like with 'regular' taxes, the collector has to maintain a certain threat level to ensure that clients keep the payments coming.