The Hitachi corporation has come out with a new generation of RFID tags, and get this: They're about as large around as a human hair and 5 microns thick. In fact, they're unobtrusive to the tune of 0.05mm by 0.0.05mm in size. They're calling it RFID dust, and it's an order of magnetude smaller than the smallest RFID chips that Hitachi has on the market, the so-called mu-chips, which are only 0.4mm on a side. RFID dust doesn't have a lot of storage capacity, at most 128 bits of data, but they're so tiny, they could …