This has the potential to be a very interesting tool indeed. It does index citations, and so gives a measure of impact... it will be interesting to see how this feature stacks up against Thomson Web of Science and other citation analysis measures. The site also links to OCLC's World Cat, so you can check library holdings in your city for any book you locate through Google Scholar.

We met Google at the Frankfurt Bookfair and had a preview of this. We are now in communication with them to ensure that NUS Publishing materials are indexed by the Google Scholar crawlers.