Why did he jump?

That's the big question he doesn't answer, but apart from that this interview in the Microsoft Architecture Journal with Don Ferguson, ex-Chief Architect for IBM Software Group and now a Technical Fellow at Microsoft, makes interesting reading. Some selected nuggets of wisdom:

You should never underestimate the importance of a social network. You don't know what you don't know. You don't know what someone may say to you that can push the reset button in your brain and make you think differently.

...communication skills matter. They really do. It's really important to understand how to write well and how to present well.

Secondly, many people who work in technology suffer from the "endgame fallacy." We are all pretty bright. We see a lot of customers. We see what they are doing and then plot a trajectory for where they will be in a few years. Once you do this, however, it's too tempting to build what they will need in five years, and not what they need next or are ready for.

Still wish he'd explained what was behind his move from the top technical job in IBM software to Microsoft though.