Here's a link from SearchCIO-MidMarket.
An Information Appliance, as opposed to any normal computer is:
• designed and pre-configured for a single application (like a toaster appliance, which is designed only to make toast),
• so easy to use for untrained people, that it effectively becomes unnoticeable, "invisible" to them,
• able to automatically share information with any other IAs.
Also check out the WhatIs article on the Turing test.