writes "Every year the Loebner Prize goes to the chatbot (and the corresponding human companion) that fares best on a Turing test administered by a panel of judges. Discover talked to Kevin Warwick, the professor who runs the competition, to get pointers on how one would go about detecting a bot. While there are some general approaches you can use, nothing is foolproof — and asking about Sarah Palin can be downright deceptive. One judge concluded an interlocutor was a bot because it didn't recognize Palin's name ... but it turned out the chatter was a French librarian who'd simply never heard of her."
The chat transcripts show how difficult picking bot from non-bot is getting.