Check the link below for a timely and balanced metadata management reality check (via Really Strategies Blog)
But everyone seems to agree that Google Book Search represents a revolutionary boon to scholars, especially people embarked on specialized research but without ready access to a university library. But is it? As UC-Berkeley professor Geoffrey Nunberg pointed out in an article for the Chronicle of Higher Education last year (expanded from a post on the blog Language Log), a research library is only as useful as the tools required to extract its riches. And there are some serious problems with the bibliographic information attached to many of the digital texts in Google Books.
Nunberg, a linguist interested in how word usage changes over time, noticed "endemic" errors in Google Books, especially when it comes to publication dates. A search for books published before 1950 and containing the word "Internet" turned up the unlikely bounty of 527 results. Woody Allen is mentioned in 325 books ostensibly published before he was born.