Quote:davidjackson: I'd point out that Google is hardly omniscient. For example, there are sections of this site to which Google has no access, but forums members do.
Yes, good point.
In addition to sections of Web sites that have the "search bots off" setting, many well-respected research databases are behind subscription walls. It costs money to maintain them and to provide peer-review services for the submissions, so one cannot necessarily find or access them in a Google search.
Google mostly searches and displays items available on the Web (to people with Web browsers), but the Internet is vast, and not everything is Web searchable or Web-browser viewable. Even if they are, the Web page is often nothing more than an on-ramp to a larger base of information that is not necessarily accessible by the public.