I think Bob Cringely got it right. Microsoft needs to transform itself and buying Skype is one of many ways it can do this. It's not clear if there is a specific strategy at Microsoft however. In this particular case, the strategy may very well be to simply keep Google from buying Skype. There's never only one prospective buyer and the reason Microsoft paid such a high price is no doubt related to Google's interest in Skype. The fact that the Microsoft antitrust decree ended on Wednesday with little fanfare is more evidence that Microsoft just isn't what it used to be.
But since we use Skype daily, my biggest concern is what will become of Skype. Microsoft has not had great successes with purchasing a product and then improving upon it. If you're were a FoxPro user, you know what I'm talking about.