Why we love anonymous celebrities like Banksy – and hate when they become known

"Simmelian strangers" like Banksy and Satoshi Nakamoto are symbolically important, writes Jonah Prousky. "They encourage us to think about an invention or piece of art — say, Banksy’s 'Balloon Girl' or Bitcoin — on its merits, without getting bogged down by the foibles, politics or love life of its creator."