I especially like the histogram with the per-month bins. It shows clearly both the tendency of developers to leave over time and the fluctuation due to release cycle.

The affiliation graph is also interesting. I think if I were to put a number on how much I liked GNOME in each year, there would be an inverse correlation with the percentage of developers that come from Red Hat (with 1999 being an outlier -- I was a fan of both Red Hat and GNOME back then).