You could hardly ask for a more dramatic example of how near zero-cost videos can expand reach and drive business. And it all started because Mary McNeight identified a problem that no one online was helping people solve.
UPDATE December 4, 2010 - I've been contacted via Twitter by people who created the Purell video including producer / director Stephen Reedy. It turns out they do not have anything to do with the company. I'm attempting to learn more. +++++++++++++++++++++++
UPDATE March 26, 2013: In what I believe is a really stupid move, at some point Air New Zealand made the video I talk about in this post private. Too bad. It had more than a million YouTube views and was serving as excellent marketing for the company.