There's no reason they couldn't provide an appliance (like the Google Search Appliance: http://www.google.com/enterprise/search/gsa.html http://www.google.com/e

There's no reason they couldn't provide an appliance (like the Google Search Appliance: http://www.google.com/enterprise/search/gsa.html http://www.google.com/enterprise/search/gsa.html) or simply make it available for a local install (like every mail server used by every company that cares about things being 'inside the firewall').