The Contributors report shows you a commit intensity graph for a specified period of time.
For Idea or Maven based Java projects, you can build graphs for separate project modules, selecting a specific module from the drop-down menu.
Below the graph is a diagram that shows you who, when, and how much contributed to the project.
The size of a dot (or a circle) represents the number of commits - hover over to see the exact number and commit details.
Hover over a committer name to see the total number of his commits over the selected period.
You can choose to list contributors alphabetically or by activity.