The searcher first sees a few results for specifically what they've entered. Then, the searcher is asked if they're "dissatisfied" with what the results they're seeing. Without needing to click, a suggestion is made and a new result(s) is listed. I'm thinking of it of variation on a traditional spellcheck.
Btw, I tried transposing letters of acronyms and also misspelling words and was unable to find a "dissatisfied" option but I rarely seem to be able to see Google UI test on my home computer.
Postscript: Google has confirmed this UI test.
Introducing... ClickZ Live!
SES Conference & Expo has merged with ClickZ to bring you ClickZ Live! The new global conference series takes on the identity of the industry's premier digital marketing publication, ClickZ.com, and kicks off March 31-April 3 in New York City. Join the industry's leading tech-advertisers in the advertising capital of the world! Find out more ››
*Super Saver Rates expire Jan 24.