The World Wide Web
A British physicist at CERN, Tim Berners-Lee, wanted an easier way for scientists to share documents, so he combined existing pieces — the internet, hypertext, addresses — into the World Wide Web, and in 1993 CERN put it into the public domain, free for anyone. Within a decade it had swallowed commerce, news, argument, and memory. It is the direct descendant of the clay tablet and the printing press: another sharp fall in the cost of copying and moving information, and another wholesale reordering of who holds knowledge and who speaks.
A new way to record or transmit information lowers the cost of copying ideas and reorders who holds knowledge and power.