In his internet talk, Harald Haas demonstrates for the first time in public how a standard, commercially available LED lamp can transmit video to a solar cell with a laptop acting as a receiver. No wifi is used in this demonstration, just light. This has massive implications for bridging the digital divide.
For the Internet of Things to go to the next level, it needs to be mostly energy neutral, which would require us to make use of existing infrastructure as much as possible. According to the internet talk, this is were "Li-Fi" technology comes in. Li-Fi internet transmits data through the light, with information encoded in subtle changes of brightness. The solar cell both harvests energy and acts as a receiver.
The speaker predicts this technology will be able to be brought to market in just 2 to 3 years.