Speaking of the analysis of common words and phrases in my Gmail from a few days ago, Wolfram Alpha developed another tool for scientific navel gazing. Their Facebook app analyzes usage habits, characteristics of your friends (age, gender, political leanings), and so on. My favorite is this graph of how my friends are connected.
The large clusters are hometown friends, college friends, graduate school friends, and Baltimore friends generally. The small clusters are friendships made at conferences. Neat.