I just watched a presentation by Jeff Patton about using personas for requirements gathering. I especially liked his comparison of personas to tests in test driven development (TDD). He argues that using personas for requirements gathering is like TDD for development. Personas are the tests for your requirements.
Like tests in development your personas should be created first and your requirements built from them. This also implies that your personas need to be specific, concrete examples from the pool of users, representatives, like tests with concrete values.
Just like tests in TDD help you design your application, personas help you understand the problem space of your application. If you can’t create a concrete persona you probably haven’t understood the problem space well enough.
Tell me a story
By centering around a specific theme, or character, the uncoordinated elements of an experience all have a clear goal and purpose. With storytelling, a diverse team creating a website or application can collectively link together the tangible elements and create something that is a meaningful experience and is more than just bits and bytes. […] Using the created personas and then creating stories about them, we are able to cast a more meaningful vision of the project.
Personas and their stories help the team understand how users will experience the built website or application and how it affects them at an emotional level.