Anil Dash has a blog post entitled Office 2007 is the Bravest Upgrade Ever where he writes

Short and sweet, the Ribbon and new UI in Microsoft Office 2007 is the ballsiest new feature in the history of computer software. I've been using Office 12 for about six months, and not only has it made me more productive, I'm struck by the sheer ambition of the changes in this version.

To clarify the point: Microsoft Office is a bigger business than most of us probably realize. Office generated $11.5 billion in revenue for fiscal year 2005, and it'll exceed that in the current calendar year. But conservatively, you're talking about a billion dollars a month.

Now, most of us who like to prognosticate and pontificate about software like to say things like "It'd be easy to just..." or "It's trivial to add..." but the thing is, most of us aren't betting our entire careers on the little tweaks and changes we'd like to make to our productivity applications. Try making a mistake that jeopardizes a business that makes $250 million a week. I'd figure a 2% error, on the order of $5 million, gets you very, very fired. Maybe they're forgiving and you can make a 10% error, costing $25 million a week. I doubt it. Most of us would lose our nerve about suggesting radical changes if betting wrong meant betting lots of jobs on making the right call. (Nobody ever got fired for making incremental improvements to Office.)

Two of the ballsiest moves I've seen Microsoft make in the past five years were both made by the Office team under the leadership of Steven Sinofsky. The first is the new UI changes in Office 2007. The second has been the movement away from proprietary binary formats and towards open XML formats as the default in Office 2007. In addition both massive changes have been live blogged all the way through by Jensen Harris and Brian Jones respectively which in itself should probably be on the list of pretty cool and risky things that Microsoft has done as well.

Now that Steven Sinofsky now runs both Windows client and Windows Live, I wonder what kind of decisions and product announcements we'll see in the coming months. So far we've been executing on stuff decided on before the big reorg, it'll be interesting to see what direction Windows and Windows Live go in the coming year or two. Definitely interesting times ahead.