A naive model of the swine flu infections (figures available at BBC news) in the UK shows the confirmed cases growing at an exponential rate (which is what you would expect). 

An initial view (mindmap, adulterated) of how model of mind fits with identity formation and perception.

This is also an experiment with XMind and in massaging the output to work in my blog here on Drupal.

I am intrigued. In general, I use a Google search to provide me with links to things I don't know, so the most obvious use for the promote/demote concept in search results is to stick the stuff I have come across before lower in the list of results, so that I can see the newer stuff more easily. Only, I suspect that if Google are 'leveraging' the information available to them from my actions, this will give them precisely the wrong impression. I imagine they would think people would promote results they found useful, and demote the irrelevant.