The central idea the we exploit in our system is simple: if physical objects can be given URLs, then we can apply web technologies to produce an information system for the physical world. Therefore we attempt to assign a URL to all physical entities, people, places, and things. The URL for a person maps to a resource for that person; such a resource may look like a web home page when rendered in a web browser, but the resource itself can be dynamic, mobile, persistent, or have other properties. The URL for a place maps to a resource that describes the place; place resources can act like containers or directories for other URLs in the same sense that place contain people, other places and things. Things can be electronic, like a printer, or passive like a painting.
For more information on the this idea, please read our paper “People Places and Things: Web Presence for the Real World”. http://www.hpl.hp.com/personal/John_Barton/WebPresence/PPTMONETSubmit.pdf
Many of our ideas would carry over if other kinds of pointers replace URLs and other kinds of systems replace the Web. However, to be a nomadic computing system we need the ability to simply access new resources and services we encounter when mobile. The web provides this feature; many other choices for pointers/systems do not. (An as yet unpublished paper by Kindberg and Fox defines physicality and ad-hoc support as key attributes of systems that support “ubiquitous computing”).