Here's the author's description of the site from a meetup group page (I remembered seeing this there recently.): http://www.meetup.com/Startup-Grind/members/15953101/

"It helps you get answers much faster with Google. The Chrome Extension immediately opens the first result when you search, and places your search results on the left in a sidebar. You can view 5 results in just 5 clicks, as opposed to 10 with regular google."

Just adding this text to the page (ideally right now while it is on the front page of Hacker News) would go a long way toward making it clear what the extension does.