You know all the social networks we use? Facebook, Twitter, Instagram, Pinterest, hell even LinkedIn and everything else? They're all just replacing old stuff we used to do by ourselves at our desks.
Twitter would be Post-Its, Skype would be a phone call, Foursquare is your globe and YouTube is the distracting window to the outside world. I rather like these old world translations to new social networks. Quick! Somebody find something that we used to use at our desks and create a social network. You'll make millions!