I'm not surprised to see MSFT include an entry about open source in their 10-K form. They're required to include a listing of risks to the business. Businesses tend to enumerate any and all conceivable risks in the document so as to not be accused of hiding information if something not listed hurts the company.

I do find it amusing that the risk they list is that the popularization of open-source software may force them to lower their prices (and therefore margins) in order to compete.

Funny, I thought that was the point of capitalism and free markets?