A recent story about paper-based wireless got me thinking that a link which eliminates a wired connection doesn't necessarily mean using radio.
Obviously, semaphore flags, smoke signals and hieliographs count as early forms of wireless communications, although since they date from before the invention of wireless, that's something of a bizarre way to refer to them.
Scientists in Tokyo have a prototype of devices that communicate without wires - by placing them near each other on a piece of specially printed plastic. MEMS electronics on the sheet detects when a device is on a particular cell, and links it to other devices on other printed cells.
I could see this as a useful alternative to USB - a specially made desktop could make communications between devices placed on it, and maybe use them as mice too.
But it that's wireless, I'd like to put Homeplug into the same "wireless" category too. It carries data over wires, but these are the power wires of the building. It doiesn't need new wires.
And Homeplug actually matches most people's home usage of Wi-Fi pretty closely. Laptops are normally used in rooms near power sockets (and plugged in more often than not). It also fits even better with the "str3eaming high definition video round the house" application which keeps coming up with regard to 802.11n.
If I'm streaming HDTV round the house, it's going to devices that are plugged into the mains. Why do I need a mobile connection?
Homeplug is still expensive, poorly marketed and not built into enough devices, With a bit more effort, it could be, in effect, wireless-over-wires.