> It's always been a question of when the supporting technology was going to be good enough to make it work.
Yep, I meant more along the lines of how you put it i.e. packaged up and ready to start selling it as a boxed-up/drop-in solution.
IBM had a commercial years ago, probably intended to be based on RFIDs, but same concept.
It's always been a question of when the supporting technology was going to be good enough to make it work. The idea has been around long enough for most of the early patents to expire.