Tim Berners-Lee combined his experience, existing ideas and several sources of inspiration into a breakthrough concept that changed the world (and we have barely seen the beginning). Component ideas of the world wide web are simple enough to be understood by a high school student, Berners-Lee's insight was to combine them in a way which is still exploring its full potential.
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Berners-Lee's original proposal to CERN is available at http://www.w3.org/History/1989/proposal.html.