A person, organization, place, idea, subject matter topic/heading, and other real world things possess "identity" --
that is, a constellation of characteristics that distinguish them from any other identity. Associated with this abstraction can be a label used as a reference, or "identifier". This is the distinction between a thing and the name of the thing.
section from IETF's Domain Keys spec. (paraphrased by me)
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The Linked Data meme is based on the use of HTTP based URIs as reference / identifier labels associated with the "identity abstraction" referred to above. Thus, when you de-reference (request information about) an HTTP based URI you ultimately end up with a resource URL that exposes the "constellation of characteristics" mentioned above, in a representation negotiated at request time -- between an HTTP client and server e.g., (X)HTML, JSON, XML, RDF/XML, N3, Turtle, Trix, others :-)
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