Given how much noise Twitter generates in the Valley ecosystem, I was surprised to find out it only has something like 300-400K users (I can't find a reference

Given how much noise Twitter generates in the Valley ecosystem, I was surprised to find out it only has something like 300-400K users (I can't find a reference right now, please correct me if I'm wrong - Compete seems to support that number though). To me Twitter is the perfect example of the echo chamber.