An anonymous reader writes: In the last three years, Microsoft claims to have entered into over 600 licensing agreements with companies small and large over alleged patent violations in "Linux". One consistent feature of all these agreements is that their contents are unknown. No one, other than Microsoft and the relevant "licensee", knows which parts of "Linux" violate which patents. Another consistent feature is that most of the "licensees" are small companies without the resources to take on Microsoft in a patent claim. However, there are a number of larger or more high profile companies that have also entered into such agreements, including Amazon, Novell, Xandros, Turbolinux, TomTom and most recently HTC. The whole situation is clouded in mystery under a veil of PR speak and mumbo jumbo. So what the hell is going on? What can we deduce from what we know so far?