Mark Shuttleworth (Ubuntu Founder, Software Visionary, etc.) has posted an interesting piece on why Microsoft is not a threat to Linux. He argues that the big threat to Linux (and Microsoft) are the IP holding firms, who essentially exploit the weak IP/patent system we have here in the US. He makes a clear case why Intellectual Property and Patent Law reforms are necessary to the continued development of software and technology.
IP Holding Firms: The Real Threat