Here is a fascinating infographic about the evolution of social media.
It begins way back in 1792 with the telegraph and shows the various cardinal points of development that eventually evolved into the intense social media network that we see today.
It is interesting to note that since 2000 there has been an acceleration of the growth of influential social networks.
This includes the growth of the inimitable Facebook in 2002 and the way that this was preceded by LinkedIn and StumbleUpon. There are also those networks that have faded from the scene to a great extent, like MySpace. However, the growth of influential and large networks like Pinterest and Google Plus after 2008 shows how social media has become an increasingly popular form of interaction and communication.