So many people who have big personalities on the internet are like that. My example is Erik Naggum. I spent a lot of time with him and the gulf between his in-person and on-line personas was vast.

Trivia: I took both the pics of him on his wikipedia page. https://en.wikipedia.org/wiki/Erik_Naggum

Had he acted in real life the way he did on c.l.l, I strongly suspect he would have been punched a lot more often. Certainly one eulogy I read of him led with the sentence: "Erik Naggum was the first person I killfiled in GNUS." On the other hand, I have heard only good things from people who interacted with him one-on-one though (whether in-person or electronically).

His technical content was almost always high-quality, but one would often need to first don one's Nomex suit to get to said content.