I first noticed this engine at SES Chicago. Someone was walking around the exhibit floor handing out T-shirts with an interesting name and font style on them - ChaCha whose logo has a touch of the CocaCola font style.
The engine itself actually uses search guides who intercat with you through a chat box to help you with your search needs. Fine if you don't mind the 30 second or so time it takes to get a response (which is fairly quick for a personal assist).
The engine, itself however, is stacked at the top with Google PPC results.
Along with regular search results, when the PPC ads are gone, there are results that its guides have added. These results can be rated by the user - Bad, Ok or Great are the options.
From the few guide results I saw it seems the engine started its push some time in October.
There is an extensive about page for more information about the site.