Usability At Microsoft
http://infocentre.frontend.com/infocentre/articles/usabilityatmicrosoft.html

Farrell, Tom
Frontend Infocentre
2001

Abstract:

The concept of the 'persona' has interesting implications for software design. It is particularly effective for reminding designers of the importance of designing for an individual, rather than the population at large. Without a concrete impression of who exactly the user is, it is easy for designers to add features continuously because 'the user' demands them. For 'user', read 'marketing department'.