Google's Docs is something of a slow burner but it has notable potential for visualisation, especially for trends and basic mapping, such as the heat map illustrated above.
The YouTube movie below provides a 60 second introduction to the Google Spreadsheet API:
We will be looking at this closer in future posts as trend/map based visualisation is often too complicated for its own good, one thing Google does well is make things easy and that can only be a good thing...
See http://code.google.com/apis/visualization/ for examples and documentation.
