In a post about the role of the personas that for several years have defined developer division's thinking about the VB user (Mort), the C# user (Elvis), and the C++ user (Einstein), Scott Bellware says:

Microsoft will probably remain bogged down in embarrassing ideologies like the Mort-Elvis-Einstein thing for the foreseeable future. At best it could only eject the developer persona junk from its marketing and product development practices, but it might never understand why it had to do so other than a mounting concern for the effect on its image stemming from its inability to insulate itself from humiliation over the progressive degradation of its tools and out-moded thinking.

I found many things interesting in Scott's post. For one, he presupposes that marketing was the team to come up with the personae (it wasn't). For another, it dovetails with some of the work we're doing in Orcas planning (for example, using scenarios). For another, he adds about fifty more layers of depth to the simple (simplistic) analysis I did on some of the research we have about VB developers.

Scott's right: the existing personae don't map to the reality. For example, on average a developer uses over 2 programming languages regularly (just think of any Web developer who typically uses HTML, Javascript, and something like VB .NET or C# and you will probably wonder why the average isn't higher).