Mark Shuttleworth on his blog makes it clear

-snip-

"We have declined to discuss any agreement with Microsoft under the threat of unspecified patent infringements."

...

I have no objections to working with Microsoft in ways that further the cause of free software, and I don’t rule out any collaboration with them, in the event that they adopt a position of constructive engagement with the free software community.

...

All the deals announced so far strike me as “trinkets in exchange for air kisses”. Mua mua. No thanks. -snip-

Lots of people threw stones when Mark started Ubuntu, and Debian die-hards saw it as the beginning of the end. In fairness, he has done outstandingly and although it hurts my ears every time i hear the word "Ubuntu" pronounced in foreign tongues (its oo BOON too) (not you-bun-to, oo-bun-to or any of the other variations that float around) it truly warms the heart to see such a huge steps made for Free Software, essentially from South Africa..

I wont get into the MSFT / Novel Novell patent discussions because theres been too much said about it already, and rightly or wrongly ill silently beam at Ubuntu's "Proudly South African" sticker!