I'm David Rosenthal. I worked with James Gosling on CMU's Andrew project in the early 80s. I was a DE with him at Sun later in the 80s working on window systems including X, and file systems. I quit to be employee #4 at Nvidia where Curtis Priem and I did the basic I/O architecture, then was an early employee at Vitria, the second company of founders of Tibco. Before I start talking about cryptocurrencies, I should stress that I hold no long or short positions in cryptocurrencies, their derivatives or related companies; I am long Nvidia. Unlike most people discussing them, I am not "talking my book".Cryptocurrencies' roots lie deep in the libertarian culture of Silicon Valley and the cypherpunks. Libertarianism’s attraction is based on ignoring externalities, and cryptocurrencies are no exception.