This is a good set of tutorials for getting started with the statistics package Stata.

Here's some useful information on how to map data the lo-fi way.

Josh Porter has the overview.

This alumni magazine profile offers a glowing, but insightful portrait of Tufte.

Aaron Schwartz crunched the numbers and it seems that a core group of 500 editors do most of the grunt work on Wikipedia, while most new content comes from casual users.