The difference between the web and email
So, if you've been listening to the radio or reading USA Today, you'll know about the "Dean remixes." You can find some here: MTV.com - News -Remixers Make Howard Dean's Scream Funky And Danceable.
What's fascinating is that a Google search at noon today found precisely NONE of them. This wasn't a web phenomenon. It spread by email.
What's the difference?
The web is about publishing something, something you can't own and can't really pass on. You can pass on the pointer, but not the thing.
The Dean remixes, like many viral things online, was passed from person to person, with no help from Yahoo or Google. When you "own" it (as much as you can own something digital) it makes it more visceral to share it.