I had some interesting interactions with him (and former deput asst secretary of treasury DeLong) on this site. https://news.ycombinator.com/item?id=17163449

He certainly got the better of that interaction and he was patient enough to continue the conversation on Twitter later. He was one of those intellectuals (like Noam Chomsky) who is accessible and engaging with members of the public. I wouldn't say I knew him, exactly, but we became internet acquaintances, and I appreciated his thoughtfulness whenever we interacted. I can only imagine how many other people had such opportunities to talk to him and will miss him like I will.