Google added a new search feature - Domain information 'Onebox'. You can now type into Google, whois domain.com and get the whois information for that domain.
Enter e.g. whois google.com to find a special link referring you to domain info from domaintools.com
When you click on the whois link, you are taken to Domain Tools. Domain Tools is one of the most widely used whois databases out there. May be it was a formal partnership with Google and Domaintools. Anyway I like nice Google feature.