It's reading data from a simple spreadsheet and displaying it here. Any changes a collaborator makes to the underlying spreadsheet will be reflected on this page. So what's new about this approach? Spreadsheet gadgets can be embedded directly in spreadsheets, like the heat map in this sheet, or even on on their own sheet. And spreadsheet gadgets can be accessed from within Google Docs Spreadsheet's built-in gadget picker, so they're very easy for everyday folk to discover and use.
For more info, check out our post on the Google Gadgets API blog.