This website is a collections of some stats computed using Apache Hadoop and Pig using publicly available Stack Exchange Data Dump from August 2012.
The stackoverflow is by no means the biggest website from the Stack Exchange collection and takes 83% of all the questions ever asked on SE.
Popularity (measured in questions per month created) for other 10 sites is displayed on the graph below. (stackoverflow not included).
For more information regarding all the 37 available sites (as of August 2012) pick the one from the list on the right ->
Colors for most of the charts are picked at random, pls refresh when unclear.