Query Refinements have changed since the earlier days of Google
In 2006, I wrote a post A Look at Google Midpage Query Refinements (Go ahead and read it; this post will make more sense if you visit the past and bring it in). The patent I wrote then was just granted again as a continuation patent, with new claims, reflecting a change in the process involving how it is being used by the Google. The new version of the patent is now at:
System and method for providing search query refinements
Inventors: Paul Haahr and Steven D. Baker
Assignee: Google Inc.
United States Patent 9,552,388
Granted: January 24, 2017
Filed: January 31, 2014