Developing a User Story Map
One of the breakthroughs of Agile software development is the idea of decomposing a very large effort in to smaller pieces, both to deliver value faster and to facilitate learning and course correction along the way. The challenge of breaking work into manageable pieces is the possibility of losing sight of the big picture, especially once a development project is well underway. The scope could become a moving target and the user experience could be sold short. If you have no reference to think about the system on a “macro” level, how can you make the best possible design decisions for your users on the day-to-day “micro” level on which we all tend to operate?
Enter the story map. It’s a simple artifact that tells the story of the product being built. It can be created with post-it notes, in a spreadsheet or using web-based tools that are entering the market for this specific purpose.
From: http://www.agilebuddha.com/agile/story-mapping-andvs-process-maps/
Jeff Patton invented this concept and his website offers examples, how-to guides, videos and templates available for use. Scrum Alliance has also adopted this strategy and recommends using it to plan projects at the portfolio, project and team levels.