I don't think Eliezer runs r/HPMOR/ ...
I seems like he does. While I've only gone to the site once the time I did (a few days ago) I saw drama about Eliezer censoring something on the subreddit and observing that this is why fan forums are better when not run by the author himself.
He's a moderator there, but he's not the top moderator, i.e. he acts at the whim of two moderators with more seniority who could remove him at any time.
Another month has passed and here is a new rationality quotes thread. The usual rules are: