What about social networks?
An interesting post by Cringely, forseeing the imminent demise of most 350 social networks. This quote, only tangentially relevant is good, but you should read the whole post from I, Cringely . The Pulpit | PBS:
"Marshall McLuhan argued that obsolete communication technologies survive as art forms. This is true, I'd say, for Morse code and movable type printing and perhaps even for your venerable Rolodex or typewriter. But it isn't yet true for CB radio, nor for most Internet technologies. Maybe they aren 't old enough yet to be appreciated. In the case of CB I think range of reception limits the possible population of players to something less than an artistic critical mass."
(from: Antisocial)