I used to be a very frequent poster on a Scottish International Football (soccer) forum - as with all of these forums, some people dominated with thousands of posts, some were infrequent, a few rude, and the majority just talked utter bollocks most of the time. In 1998 Scotland qualified for the World Cup in France, our first World Cup since 1986, and it was boldly suggested that there should be a meet up of forum posters in Paris before one of the games.
Some people did fit their profiles, others were vastly different, and in some cases of a completely different gender. The loudest posters were almost all pretty much the shyest in the bar, some struggled with basic social skills, and some just couldn't back up their bite when confronted with actual people face to face. But no one was as bad as they appeared on the forum
One thing I would say. After that meet up in 1998, I am still close friends with a significant number of people I met that day. Have travelled the world with them and they turned out to be some of the kindest, smartest, funniest people I know. Though none of them really fit their online persona, I think, in hindsight, if I looked back you could probably catch glimpses of their personality between the lines.
It's also fair to say, some were and are to this day, complete assholes : )