In a series conversations with people, the winning robot, named Elbot, fooled 25% of its interlocutors into believing it was a genuine human being. A score of 30% would have been sufficient to pass Turing's criterion for a true artificial intelligence.
From Nicholas Carr
The University of Reading explains more.
As part of the 18th Loebner Prize, all of the artificial conversational entities (ACEs) competing to pass the Turing Test have managed to fool at least one of their human interrogators that they were in fact communicating with a human rather than a machine. One of the ACEs, the eventual winner of the 2008 Loebner Prize, got even closer to the 30% Turing Test threshold set by 20th-century British mathematician, Alan Turing in 1950, by fooling 25% of human interrogators.