Take a look at this post from A Zulu in Silicon Valley. It looks at a search engine called Quece that actually searches by chat. They call it Conversational search. You search like you think. Simply type in your search, get results, and then you are asked another question, thereby refining your search. This sounds awfully like a reference interview. I haven't tried it out yet but it is certainly added to my to do list. I'll be keeping on eye on this one.