"...The announcement confirmed that Microsoft was planning to use its software patent portfolio against interoperating products by requiring a patent license for all commercial activity [...] Microsoft's patent licences are incompatible with Free Software [...] Free Software's freedoms to use, study, share and improve software without additional restrictions are key to the success and utility of Free Software in both commercial and non-commercial ICT infrastructure. They are also the basis for many of today's working examples of interoperability and competition..."

Prominent legal counsel the Software Freedom Law Center said that the legal terms covering Microsoft's Open XML document formats pose a patent risk to free and open-source software developers.

"The changes mandated by the European Commission in Microsoft's interoperability licences will continue to block Open Source developers, legal experts on this type of software say..."

Microsoft's pledge to truly interoperate with the rest of the planet, including open-source developers (both commercial and community), leaves two clear victors in the Linux camp: Red Hat and Ubuntu. While Novell capitulated to Microsoft's early demands for a patent stooge, Red Hat and Ubuntu stood firm.

Microsoft Relevant Products/Services is targeting Sun Microsystems for patent violations in its open-source software, claiming OpenOffice.org breaches 45 of its patents. Sun wasted no time in responding to the claims coming out of Redmond.

Microsoft irrevocably promises not to assert any Microsoft Necessary Claims against you as an open source software developer ("You") for making, using, importing, or distributing any implementation of a Covered Specification ("Covered Implementation"), subject to the following.

One might have thought Microsoft was back rattling the patented software sabres against Linux and open source this week, reading some of the recent reports regarding Redmond’s patent infringement suit against automotive navigation and GPS player TomTom. However, upon further review, it seems that Microsoft is making a point to say that these suits are not aimed at the Linux OS or open source.

Is the open-source community stealing ideas from commercial vendors? IP Innovations seems to think so; the patent-holding company recently filed a lawsuit for patent infringement against Linux distributors Red Hat and Novell, claiming that Linux uses ideas originally developed at the Xerox PARC laboratory.

Open-source software company Red Hat has said that it is concerned that Microsoft patent arrangements may not be compatible with open-source licensing models.