What really happens on Twitter these days? People have self-sorted into cliques, little in-groups, tribes. The purpose of tribes is to defend their beliefs, their ways, their customs, their culture — their ways of seeing the world. The digital world is separated into “ists” — it doesn’t matter what, really, economists, mens-rightists, leftists, rightists — and those “ists” place their “ism” before and above all, because it is their organizing belief, the very faith that has brought them together in the first place. Hence, to them, it’s the totem to which everyone, including you, must pay homage, and if you dare n…