I’m guessing he’s probably talking about LessWrong, which nowadays also hosts a ton of serious safety research (and is often dismissed offhandedly because of its reputation as an insular internet community).
Yes, LessWrong and the Alignment Forum have a lot of excellent writing and a great community. It may not be to everyone's taste, however.
For people that have demonstrated various levels of commitment, such as post-graduate study and/or continuing education, there are various forums available.
I'm also interested to see what other people have found.
I flagged the comment above because I think it doesn't belong here on Hacker News based on our guidelines. They help us understand our shared norms here.
Like where?