A graph from a 1954 article by Ernest Jawetz in Annual Review of Medicine looks remarkably similar to the Gartner Hype Cycle "discovered" in 1995. Both graphs have an enthusiasm peak, a disappointment pit, and a productivity plateau (see below).

Gartner Hype Cycle (courtesy wikipedia.org)

With Twitter we are probably still in the early stages of the cycle (see Google Timeline snapshot):

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