Five (5) Reasons Why Academic Librarians Can’t Ignore Google Scholar, from the UBC Academic Search – Google Scholar Blog

For my money, reason #2 is the killer: GS will now contain on the order of 800 million to 1 billion citations, thus making it probably one of the largest scholarly citation databases on the planet. Ignoring that is like ignoring the elephant in the room.

And, I would just like to add, interesting that UBC has a blog devoted to GS.