The dispute over alleged patent infringement by Linux continues:

Linux group calls Microsoft's bluff

The head of the Open Invention Network (OIN) has dismissed Microsoft's claims that Linux violates over 200 of its patents.

OIN chief executive Jerry Rosenthal said that Microsoft's assertions are simply an attempt to undermine the open source movement.

Rosenthal added that it is time for Microsoft to reveal the patents that are supposedly being infringed, or to drop the claims.

Canonical CEO Mark Shuttleworth, speaking about Steve Ballmer

Microsoft CEO Steve Ballmer has once more claimed that Linux and open source violates Microsoft's intellectual property and patents. Canonical's CEO Mark Shuttleworth thinks Ballmer has it all wrong.

Ballmer made his claims about Linux patent liability back in November 2004, and his claims were disputed at the time:Microsoft reignites its war on Linux
Here is what Ballmer actually said:

Number two, on licensing costs I would say two things. First of all, I don't know that it's clear to anybody what the licensing costs are for open source. Today, people say, well, isn't it just free, but we don't know in the long run. Open source software does not today respect the intellectual property rights of any intellectual property holder. There was a report out this summer by an open source group that highlighted that Linux violates over 228 patents. Some day, for all countries that are entering WTO (World Trade Organization), somebody will come and look for money to pay for the patent rights for that intellectual property. So the licensing costs are less clear than people think today.

This casts aspersion upon Linux without providing any evidence and by itself might be dismissed as FUD except that in May 2007, the charge was repeated by Microsoft general counsel Brad Smith: Microsoft takes on the free world (Fortune magazine)

Microsoft General Counsel Brad Smith and licensing chief Horacio Gutierrez sat down with Fortune recently to map out their strategy for getting FOSS users to pay royalties. Revealing the precise figure for the first time, they state that FOSS infringes on no fewer than 235 Microsoft patents.