This is a great introduction to Web 2.0 for normal people. It has an obligatory Flickr reference, of course, and is posted on YouTube. Watch it below. Thanks to Alice Marshall for pointing this out — I agree with her sentiment that videos like these could replace many PowerPoints. It obviously takes a bit more skill to craft video, but the impact is much more dramatic than simple slides.
The video itself was created by Michael Wesch, an assistant professor of cultural anthropology at Kansas State University. Nice work.
UPDATE: John Battelle has a great interview with Wesch.