Recently I read about a technology being worked upon in UC Berkeley that combines digital circuitary, wireless communication and Micro-electronics for mechanical devices. This project is called "smart dust" - which is pretty much that, thousands of really tiny sensors that can just be thrown in any area of interest, to measure and collect data.
The really cool part of smart dust is that these dust particles can transmit information passively. They have a mirror like component whose angle can be changed by tiny motors in response to external stimulus. Then to "transmit" information, you just need to throw light at them. Sounded like sci-fi to me -- How do you make such electromechanical devices that work to such precision?
Then I came across another bit of technology that does something very similar with mirrors. This is the proprietary DLP technology owned by Texas Instruments and used in Projectors. It basically consists of a matrix of really tiny mirrors, each mirror representing a pixel. Different angles of mirror positions give different colours, controlled electromechanically with very high precision.
So while we may not soon be seeing a huge room full of tiny smart dust particles, tracking one's movements as we walk, changing the wall colours after measuring the facial expression and mood (??) , it certainly looks like a possibility for the future..A lesson to me that things are not sometimes as bleak as they seem :-/.