I"m not sure yet whether I have a dog in the Mono fight, but a couple of comments today from Nat and Havoc have me confused, so perhaps one or the other or both or some other smart person could elaborate:

Nat:

Should we not use XML because much of the standard was developed by Microsoft; because, in fact, Microsoft claims to have IP on it?

Havoc:

Yes XML had Microsoft involved, among many others. I'd say the difference between XML and .NET is pretty clear so I won't belabor the point.

In fact it's not terribly clear to me, but maybe someone smarter and more knowledgeable than I could do the "compare and contrast" thing between .NET and XML to help me understand the ways in which the situation may be the same (or at least similar, the Nat argument), and the ways in which it is not (Havoc's apparent position).