This Wall Street Journal graphic shows who's selling (or sold) a percentage of their Facebook stocks and who's holding steady.
This graphic is the perfect example of why I'm a proponent of the pie chart. First, they stuck to two values per pie chart. That makes it easy to read. Next, they used the size of the pie to denote the number of shares. Finally, they used small multiples to easily compare both the shares owned by each entity as well as change in percentage of shares being sold.
I'm sure bar charts would be fine too, but WSJ really used all aspects of the pie chart very effectively.
[via Barry Ritholtz]