User Stories.

User stories are part of an agile approach that helps shift the focus from writing about requirements to talking about them. All agile user stories include a written sentence or two and, more importantly, a series of conversations about the desired functionality.

What are user stories?Agile Alliance
User storyWikipedia
User Stories: An Agile IntroductionAgile Modeling
User StoriesMountain Goat Software
10 tips for writing good user storiesRoman PichlerMarch 24th, 2016