Raikes, in a phone interview Thursday afternoon, said:

"The key thing is, you know, we're always growing, and so everyone on my leadership team has great responsibility, and they are growing there, and Stephen Elop adds an additional level of skill and experience that I think really helps to complement what my team is doing. Part of the way in which you set the company up for continued growth is you add additional leadership. Sometimes that's by growing it internally and sometimes that's by acquiring it externally. That's always been our strategy, and Stephen Elop, is just a great opportunity for us to add to our overall strength of leadership."

MSFTextrememakeover, like many observers, was caught by surprise by this announcement:

"My initial reaction -- 'Wow!' Didn't see this one coming. Gates, Ballmer, and Raikes have effectively been the top echelon of the company for as long as I can remember. With Gates having already announced his retirement this year, and now Raikes as well, that leaves just Ballmer from the original troika."

Elop "seems to have the right pedigree," the blog continues. The transition period -- about eight months by the time Elop arrives in Redmond -- is "fairly decent." "But Raikes did a solid job with Office and was widely seen as the leading candidate to succeed Ballmer. So combine that with some other recent high level departures, and I don't think the market is going to respond positively to the news tomorrow."

In fact, Microsoft shares are down about a percent at mid-session, but the broader indexes are also in the red, so it's tough to tell how much of Microsoft's decline is a reaction to Raikes.