While I don't actively target the Linux platform, I have always been comforted by the Mono Project. That cross-platform-.NET project gives me a feeling that my .NET work could at least partially be ported to other targets if a need arose, removing the vendor lock-in to Windows when using the .NET platform (even though I have never had the need to use it, I pursue the same target when developing in C++). Every couple of months I install the latest incarnation of Mono on a Linux virtual machine, copy over an assembly (ensuring that it uses only features that exist in Mono), and run it, and it really is a little bit of magic when it runs successfully (and quickly I should say - the performance on Mono is spectacular).

The thing that I don't get, though, is the bubbling animosity Microsoft displays towards the Mono project, and the legal uncertainty some within Microsoft continually try to create around Mono. Don't you realize, Microsoft, that Mono is one of your greatest allies? That .NET has been sold within countless shops based upon the argument that it was "cross platform", courtesy of Mono, and that the worries of the executive that Linux needs to be considered are all taken care of, again courtesy of Mono? Microsoft really should be sending Manuel a big, fat commission check.

I can appreciate that Microsoft doesn't want anyone usurping their creation, but really - in virtually every rational situation Mono is a winner for Microsoft.

• It helps sell .NET as "cross-platform"
• It will always be one step behind, ensuring that Microsoft has the upper hand. Sure, it'll implement some technologies (such as vector graphics) more quickly than the Microsoft's .NET framework, but to most developers that is non-standard, and instead it'll "really" come out when Microsoft releases it (and Mono will then have to play catch up)
  
• It's training loads of Microsoft-hating OSS lovers in the ways of .NET, drawing them away from other superb environs like Python. A very large percentage of the people targeting Mono would have targeted Python or J2EE or C++ otherwise.
  
• It helps Microsoft compete on their "home turf"

Microsoft really needs to put down the gauntlet, embrace Mono, and remove the legal uncertainty around it.