RFID tags are tiny chips that carry product information and emit radio signals. Unlike bar codes, they don't have to pass under a laser scanner. This technology will probably be the "next big wave" so to speak. Texas Instruments Corp. and Globeranger Corp of the Dallas, TX area are developing products on this technology. We may see different types of the chip emerge as time goes on and things develop. Home Depot is doing some pilots with it now. Walmart hopes to save a billion annually as a result of the chip. Your electronic tolltag is one example of this type of technology. There is the Exxon "speed pass". Tiny chips are used to track animals. Car manufacturers use the chips to track vehicles, keys, etc. Costs of the chip keep coming down. It has gotten to as low as 30 cents now, but when it approaches a nickle we will see widespread use in the retail sector. So, to answer your question...you have probably noticed some items which have it already, but the chip could vary in appearance depending upon the application or the evolution of development. It should be very small, about a half inch or so and relatively thin. There is even talk of "automatic checkouts" -- where you just roll your cart on by the register area and everything is automatically totalled. There is discussion of invasion of privacy, because these chips can be monitored for marketing purposes and individual items can be located.