User personas are an InteractionDesign tool that helps developers make the right decisions about features. A user persona is always a common user of the application and never an uncommon user. Linux development isn't based on user personas and the story from Luke Kanies at http://luke.hates-software.com/2004/02/28/3b08b06a.html illustrates this.

User personas are a polite way to say "Well, fuck that guy." about someone who's 0.00001% of your target market and whose needs conflict with 99.9% of it.

----
CategoryInteractionDesign