Here's a video clip of a guy navigating his Second Life Avatar with his brain. It is speculated that this could help people with Locked-in Syndrome, a rare affliction that was the topic of "The Diving Bell and the Butterfly," written by Jean-Dominique Bauby. This would potentially allow these people to communicate more effectively - certainly more so than Bauby's pain-staking process:
"The entire book was written by Bauby blinking his left eyelid - in July and August of 1996. A transcriber repeatedly recited a French language frequency-ordered alphabet (E S A R I N T U L etc.), until Bauby blinked to choose the next letter. The book took about 200,000 blinks to write and each word took approximately two minutes"