Modern history of human communication
With the announcement of Google Voice for everyone, the big G describes the history of human communication in the graphic above - and consequently, how Voice is the next step in the evolution. We begin with the tin cans in 1810, to the telephone in 1876, then the first email in 1971, and tada, we arrive at Google Voice in the present. Average international call cost per minute serves as the backdrop.
I gotta get me one of those vintage mobile phones of 1979.