Summary of a talk by Andreessen Horowitz analyst Benedict Evans. The four technologies are autonomy, mixed-reality, cryptocurrencies, and artificial intelligence. But more interesting is some of the discussion around these, and especially the commentary on 'S-curves' which track the adoption of new technologoes. "In each case, as the curve matured, the question became less about the technology itself and more about what could be built on top of it. That’s where we are with the mobile internet, with things like ride-sharing, Instagram, Instacart, and other things we can do with our phones today."