(with all due apologies to John Steinbeck, and noting that my mother would be happy that I knew the author without having to look it up. (though I did check to be sure)).
Robert (who gets no special "use my last name" treatment here) wrote a post entitled Ethically bankrupt personas, a line pulled from a Scott Bellware article entitled Mort or Elvis? A question for a Bygone Era. Which led me to this post...
The existence of developer personas (well, to be pedantic, the outside knowledge of the existence) has led to a considerable (and in my mind, somewhat unwarranted) amount of angst around the underlying meaning of the personas.
It's certainly true that the names of the personas - Mort, Elvis, and Einstein - haven't helped things (though "Elvis" has been fairly benign, and forced one of our PUMs to come to a team meeting dressed as Elvis, a picture that was featured on an early C# website (now *that* would have been a good trivia question).
But in the end, personas are a tool that the VS teams use to help make decisions about how the product should work, and as a shorthand when talking about their users.
Or, to put it a different way, it's about differences in philosphy and work styles between developers. And there are pretty big differences, and woe to you if you don't keep this in mind. If you're building a C# product, you need to know Elvis well. If you're building a library or platform that you hope will be used by all the personas, you're likely going to disappoint one or more of them (I will note that it is certainly possible to disappoint all three, though good manners preclude me from giving examples).
So, I do see the value of personas, if only as a first step in trying to decide what will be less or more important for your users. But I don't think it's a replacement for talking to your users to find out what real people think.
The Windows group also have their personas. The one we care about most in the DVD Maker work is one named Abby.
I should also note that I'm in agreement with Scott on the whole Agile side of things. When I was within that C# team, I was a vocal advocate (among others) for providing support for customers working that way (and even for using it ourselves), but the value of Agile is still working its way into the Microsoft psyche. From what I've seen, VS Team System is not the answer I was hoping for.
Of course, you may want to discount what I say, since I'm a prototypical Elvis...