The Google Visualization API (Google Visualization Playground ) can use a Data Source such as Google Docs - Spreadsheets. Using several combined visualizations to create a Dashboard.
Dashboards are now becoming very popular embedded in websites , Google Analytics Dashboard is an good example, most website developers would be familiar with. One of the most powerful visualizations in Google analytics is the intensity map, which helps see organic/campaigns strengths instantly form particular countries.
Gadget URL: http://www.goopal.org/Google-Sites-Embed/gadgets-xml/intensity-map-visualization.xml
The countries must be in ISO Characters (ie. United States = US , Germany = DE etc...)
So Google Visualization API allows you to use many Data Sources and even lets you query the results. This has great potential for Simple Database type Queries which can also be instantly visualized.
This Google Gadget uses the Google Spreadsheet for it's Data:
Notice the Range in the spreadsheet is set: &range=A1:E27
Below is an example of a intensity map which displays data according to each country.