I just came across this beautiful TED talk by Prof. Harald Haas of University of Edinburgh, UK. He explains and demonstrates the upcoming Li-fi technology using the visible light to get a wireless communication. Li-fi replaces our commonplace wi-fi technology that uses microwaves for data transfer. The key role in this technology is played by the light emitting diodes (LEDs), whose off and on state can be exploited as digital signals.
I could not get time to go into detail, but this article has a nice introduction of this promising technology.