google have many data centers, different users will use a different data center for the search - when they do a major database update it sometimes takes weeks for the changes to replicate to every data center - although I'm not up to speed on the new big daddy data centers update process, but yes there are multiple data centers
btw, you'll get the same results from any google URL you load - all domain names point to "the closest data center", someone else in the same country may get different results though - it uses distance in terms of route over the Internet rather than distance in terms of closest physically
