The usability consultancy I work for, UsabilityOne, is now one of only 16 companies worldwide to become a Google Website Optimiser Authorised Consultant. This is very exciting, as I believe that Google Optimiser (sorry, I refuse to spell it with a Z) is a product that when used properly can reap amazing returns.
We have already had a number of success stories using this tool for several of our clients. One of the reasons the UsabilityOne has been recognised as expert vendors with Google Optimiser is our solid background in user behaviour gained from our constant real user testing. The designs and variants that we suggest to our clients are developed from having spent hours observing users interact with sites in real time, which translates into understanding which designs to trial, and how to best interpret the results.