People can communicate through the power of thought alone - with a little technological assistance. Christopher James, a researcher at the University of Southampton's Institute of Sound and Vibration Research, found that thoughts could be transmitted over the internet via brain-computer interfacing (BCI). The process involves translating the thought into a series of binary digits, which are then transmitted to a second person's brain through a flashing LED lamp.
The experiment can be seen at: http://tinyurl.com/ydrzspw.