Someone just forwarded to me a viral video from MoveOn.org that I love. In fact, I forwarded it to about half a dozen people myself. As I write this post, their counter states that it has been sent to 9.2 million people (one can never trust counters like that, by the way).
I love it because it is entertaining and pretty effective, at least in delivering a message. I don't care about the particular political position it takes. I love it because it's a very entertaining way to send a message to people to get out and vote. I would love to see if it actually delivers votes, but I doubt we'll ever know.
I would love to use a viral video like this in a marketing campaign, but there's one problem. The ability to predict the popularity of a video is very limited. The Jib Jab guys never were able to replicate their original success with follow-up videos, and YouTube is a graveyard of attempted viral hits.
As I mentioned in my radio post, home runs are hard to predict. To extend that baseball metaphor a little further, base hits are far more predictable and drive in just as many runs.