These are the slides from the talk I gave at Techdays2010 in Portugal (http://www.techdays2010.com/Event/Session/Details/natural-user-interfaces-a-3a-vaga).
The way we interact with technology has suffered great changes in the last couple of years. Ever since the invention of the command line interface that we have been seeing changes in the way we interact with technology. Today we have touch technology on our PCs, cellphones, GPS, we use voice commands to control our cars, and we even use gestures to play video games. But we need to understand the differences and resemblances between the different modules of interactions and there "ancestors" so that we can truly take advantage of this change. In some ways like when the GUI came out, NUI are here to stay, and its our duty as IT professionals to take the maximum advantage of this new technology and new way of HCI.