There are many cool visualization techniques that look cool and are loved by engineers, by not necessarily very useful by itself. However, when observing developers interacting with these visualizations, the authors observed that they started explaining the story of the code. Like “ow, remember, this is where I fixed this bug, it was so hard”
Storytelling comes from data journalism and is popularized by the New York Times and the Guardian, and the authors propose to adapt this technique for SE. They state that storytelling is gamifications lesser known sibling, and that gamification might lose its value over time, because people feel they are not rewarded enough.
So the idea is to visualize a code base timeline and allow users to add lifetime events to it as shown in the figure to the left. This, to me, seems like a very nice idea, and fun way to share the story of a project in an interactive way.