On the one hand, I must say that when a company spent a lot of money building on what is their asset on the market (like the .NET), it's their right to ask for a license fee if somebody is using this knowledge to open softwares on others platforms and earning money to be the first to be able to do so. The .NET in the end had been developed out of Java as platform independent to tie people to Windows. Giving it for free would not be fair to all people who are paying at the moment (like Samba). It will probably be only when softwares will get cross platforms that Windows will stop seeing it as an advantage. When you install the .NET, you get a message that knowledge out of development should not be released to the public. Now that Wine start to be able to get a full log of the .NET inner components, it's smarter to say, now Microsoft opens the NET than to wait for the news *wine is installing the .NET builtin on Linux using Wine API* (as NET is officially available to all platforms) or with a windows dlls to unix converter. With Wine's progress they have to make a move forwards to keep the news. Please note that they said they are also opening only documentation of Vista (which is at the moment not so popular) but said they will not disclose of XP because it's too old (although it would probably be more interesting to users here).
