As a technical writer, I am constantly thinking about how to help readers absorb and retain information. It's not enough for my documentation to be correct and complete; it has to be useful to readers in that it results in a more effective user experience. So the metric of quality for software documentation is how well users can use the software (in full realization that nobody likes to read the documentation and will consult it as little as possible). That means that I have to be very creative when creating help.
Re the above video, it's exciting to see someone who got creative about statistical reporting with such success. They have not only created more sophisticated analysis and a zippier view (using a Google gadget called motion charts), but he has turned a statistical lecture into storytelling.
I have long believed in the importance of an emotional element to help people absorb and retain information. I once read an abstract of a PhD thesis in technical writing that found people retain information better if it makes them happy - but I suspect happiness is just a subset of emotions that will achieve the same end. I recently saw a lecture (I've lost the link, unfortunately, but it was on TED) about how graphics engage different parts of the brain and get people to make connections that words alone cannot make.
Seeing this brilliant statistical presentation approach reinforces something I've thought for a long time: documentation should have graphics: cartoons and photos as well as UML diagrams and screenshots. As an example, I have an old copy of The Complete Idiot's Guide to Java 2, and it includes a repeated cartoon of a woman yelling out, "Hey stupid!" with a caption underneath that gives a little bit of info about Java. More than once I have flipped through the book reading all the "Hey stupid"s with rapt attention.
On one hand the field of technical writing is prone to a lot of gimmicky ideas and useless bells-and-whistles. On the other, it is held back by localization concerns: many cultures are said to object to representations of humans (even of hands), and Germans are said not to appreciate humor in business, and generally we are warned not to try anything funny in case it offends someone. Nevertheless, I think graphics are integral to engaging readers and should be considered more seriously as core elements of good documentation.
I specialize in documentation for developers, and mostly write reference material, tutorials, and very dense user guides. My books are not read cover to cover, but are generally read piecemeal as the developer needs the info. So not just any graphics will do: like Hans Rosling's statistical presentation software, above, we need to develop really effective, engaging graphics. Graphics that not just provide useful information, but that engage the mind in a novel way.
For more on the new approach to presenting statistics, and lots more examples of it, see gapminder.org.
Update: The lecture I was thinking of is Tom Wujec on 3 ways the brain creates meaning. The comments provide some needed caveats.