I don't think killer app is the way to think about it. Blogging has been a world changing technology (though ho hum by 2013 standards), and back in 1999 (when b

I don't think killer app is the way to think about it. Blogging has been a world changing technology (though ho hum by 2013 standards), and back in 1999 (when blogging was at its infancy), what would you have replied was the killer app of Blogging?