From the article:

“Q: On a related issue, do you worry that GNOME is becoming too involved and enmeshed with Microsoft technologies? If the patent problem with GNOME becomes too great, might you switch to KDE one day?

A: I think it’s very healthy that we have multiple desktop platforms, and that they’re both committed to free software and sources of innovation and inspiration and competition. We picked GNOME mostly because of its approach to the release cycle and because it had a real strong commitment back in 2004 to usability.

Since then, KDE has also embraced the idea of usability as a primary driver, and they’ve done some really interesting things on the technology front. I keep a level of awareness of KDE, and I run KDE at home just to make sure I have a sense of where it’s going and how it is doing. I like the rivalry. We might [switch]; it’s good to have that option.

…

With regard to GNOME and Microsoft, I’m not concerned. My view is that to win, you have to have your own vision. You have to have a very clear idea of what you can deliver that’s unique. You can’t go around sort of chasing someone else’s coat tails. So while I respect the people in the free software community who invest a lot of time in making compatible implementations of other people’s technology, I don’t think that’s the real recipe for success for free software. We have to give people a reason to use our platform for itself, not because it’s a cheap version of someone else’s.

And in fact, the real successes of free software have been the places where it has just blown away the alternatives. The Internet runs on free software, and not because it has copied anything from Microsoft. The proprietary software guys like to accuse free software of not innovating and not doing anything other than sort of walking down the same path that they’ve already walked, which is always easier. That’s just not true, but guys like the Mono Project are reinforcing that stereotype.”
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Now, I don’t see Ubuntu switching over to KDE as primary DE anytime soon, but there’s the possibility that if Gnome falls too far behind KDE, it might fall from Ubuntu’s favor. Not to mention what the consequences of too much mono infestation might eventually do to Gnome’s standing in Fedora/Red Hat/CentOS. And the history being what it is, getting tied too closely to Redmond has a good chance of leading to falling behind technologically.