For those sharing my GUID fixation... work from MIT may seal the deal:

We're just at the beginning of a new age of products, devices and objects
that talk to us -- and to each other. "We're really talking about the next
50 years of computing," says the executive director of the Auto-ID Center
at MIT, which is one of the organization studying ways of using computer
chips embedded in tiny pieces of plastic attached to just about everything,
including egg cartons, eyeglasses, books, toys, trucks, and money. The tags
are currently known as Radio Frequency Identification Tags (REIG), and the
Auto-ID Center calls the core of its standard "ePC" or Electronic Product
Code. Companies such as Wal-Mart, Gillette, and Procter & Gamble have
committed to using the technology. As for privacy issues? Accenture
scientist Glover Ferguson agrees that privacy will be an issue, and says:
"There will have to be a social discourse about what we want and don't
want. But the technology isn't going away. You can't un-invent it." (

http://www.techknowtimes.com/jump/v5i15022.html