There is an interesting visual search feature in the HathiTrust Digital Library. Call number, language, and date, for both the entire HathiTrust collection and public domain works are available. The visualizations are colorful and created in flash on the screen. Roll over a piece of the pie and stats will appear, (i.e. DS – History of Asia, 157616 items), click on the pie piece and results for that variable will be displayed.
Here’s a HathiTrust sample chart – but not interactive.
Thanks to Gary Price from Resource Shelf for showing me this cool feature.