Google results with a time line

Google has introduced a new experimental method to list results using a time line. The results such as this one on "nanotechnology"will show the results based on the word and the date it is related to.

The idea works fine with the examples they have given, but for some of the newer words created post google, they better use the information as to when it was cached. If the cache is not backed up, its hight time they started recording the dates on which new words were found by the google bot. This has many advantages to the casual linguist and also provide a more reliable time line for the future.

I wonder whether the site map can have data which can be used to build the time line. The map view is more of a browser version of google earth.