There is more to it, I just posted it as an example.
If you want more proofs here:
I hope you read all license agreements related to the whole framework.
A short summary, you have the point where Microsoft "promises" not to use their software patents against you.
Then you have multiple licenses for the framework that inclusde MIT, BSD and various GPL licenses.
Another point is if you embed the framework into an open source project, the .exe needs to be exchangeable and separate at all time, if you compile it into your project, then this is not possible, then you need to buy a license.
It looks like they really opensourced most of their stuff now:
http://mono.1490590.n4.nabble.com/Embed ... 62200.html
http://www.infoworld.com/article/305073 ... cense.html
But I'm still sceptical, probably they updated their license to get more stupid users to use their stuff. It looks like they still sell their license, the question is what that is supposed to be for.
Overall I think it is still dangerous.