Just a bunch of statistics and graphs from playing with Facebook data in Microsoft Excel:
Of my 232 friends in Facebook, 209 have their birthdays specified, and just 145 of those also specified the year that they were born.
Here's an age distribution graph of my friends (more accurately, the age that they turn on their birthday in 2009). The youngest is 14, and the oldest is 63. There's a massive spike at 25, since that's the age of most of my high school and college classmates. I'm actually 24 myself, and a year younger than most of the people in my class. This graph may be biased against old people, who I assume are more reluctant to reveal their age.
I was able to divide my friends into five categories with very little overlap: Family (including many extended relatives), high school, college (including faculty), work, and others. College people are the biggest slice of the pie. The majority of the people lumped into "others" are known to me mainly as friends of friends, plus some other people that I simply do not remember but would feel guilty removing since we have a lot of mutual friends. Haha...
Any other ideas for graphs?