“Two out of three ain’t bad” is the title of a Meat Loaf song but is also the idea behind triangles: situations in which you can achieve only two of three objectives. The classic example is the idea that in manufacturing you can have any two, but not all three from fast, cheap, good. (*) Much of the current debate about social media and how to regulate it is people shouting loudly past each other because they are pursuing different objectives in what I believe is a social media triangle: Free...