You've heard of Wi-Fi, now you need to hear about Li-Fi. Still in the nascent stage, this new technology could change how you use the Internet. It's much faster than existing Wi-Fi tech, it's more energy-efficient, and potentially more secure as well. But of course, there are just as many downsides. Li-Fi, or Light Fidelity, is suddenly in the news these days because an Estonian company called Vel