As long as I'm mentioning DataPlace (see previous post), I should point out this talk on video from Troy Anderson.

Here's Google's abstract of Troy's Tech Talk:

Organizing the world's information is great, but you end up with a lot of GIGO. While technology can clean up some things, without human intervention, you're still going to be left wanting. See what happens when cleaned up geodata meets some of the more pressing problems facing society today; and the humorous, or less humorous side, of what happens when you don't bother.

Check it out.