Roles of Design on an Agile Project

A note from Tom on the course he teaches about helping the business people specify requirements in an Agile world:

"The key concept is that all the classic analysis techniques used for requirements, analysis, and design work are still valid and valuable but they should be viewed as techniques for shaping the conversation among all the people designing the business process/product, not as formal, complete, version controlled documents. Manage the work with story cards (see Mike Cohn’s User Stories book). Manage the conversation with agile modeling techniques (see www.agilemodeling.com) and record and version control Customer tests."

Looking at the agile modelling site it has matured alot from a few years ago.

It seems to me we have a lot of people (Eric Evans, Tom Poppendieck, Scott Ambler) saying similar things. Customers and developers must share a model of the system - even though that model evolves.