The CEO of a purchased company is often a redundant position.

This is almost exactly 18 months after the acquisition. Guy probably finished his earn out and is moving on. Nothing surprising for an acquired CEO.

Your comment seems a bit trite and overly dismissive, which is why it has been downvoted into oblivion, but there is a possible grain of truth there to watch out for.

It has been rumored for a while that Scott Forstall, head of iOS, is extremely difficult to work with, and has been the reason for a number of people leaving Apple. I can't even begin to guess whether this is true or not -- I don't have any way of knowing. But this may actually be something to watch for over the next couple of years.

Well, even Google (with its great working environment) has issues keeping personnel from acquisitions.

I think Yahoo leads in botched acquisitions.