For EAs and people interested in discussing EA, I recommend the EA Corner Discord server, which I moderate along with several other community members. For a while there was a proliferation of several different EA Discords, but the community has now essentially standardized on EA Corner and the other servers are no longer very active. Nor is there an open EA chatroom with comparable levels of activity on any other platform, to the best of my knowledge.
I feel that we've generally done a good job of balancing access needs associated with different levels of community engagement. A number of longtime EAs with significant blogosphere presences hang out here, but the culture is also generally newcomer-friendly. Discussion topics range from 101 stuff to open research questions. Speaking only for myself, I generally strive to maintain civic/public moderation norms as much as possible.
Also you can get a pretty color for your username if you donate 10% or do direct work.
Hi! There's been a couple of good answers so far. As far as I'm aware, the Russian LW slack is very much alive and active, and as far as I know namespace's diaspora map is the most comprehensive list assembled as of now. The LessWrong IRC and Slack, as far as I know, remain active and populated by many intelligent and worthwhile conversations.
That said, the Discord section of the diaspora map has gotten pretty out-of-date; a lot of the chats listed have either died, gone dormant or been subsumed by others (or, indeed, have increased in stature greatly through the process of subsuming). I would update it, but I don't appear to be able to edit the page.
While a comprehensive conspectus of the rise and fall and death and rebirth of "rats' cord" is far beyond the scope of what I can type out in a single post, and while I am indeed currently writing up a post that goes into excruciating detail of statistics kept over the last two years (including graphs!) I can at least give a brief overview right now.
There have been, by various estimates, anywhere between ten and a hundred "rat discords" created over the course of the last two years. As of 2019 March 31, there are only three with a monthly average of more than two thousand lines posted per day (to wit: slate star codex, r/rational and mine). Interestingly, these are also the only three with a monthly average of more than one thousand lines per day.
This is by no means a comprehensive assessment of the social landscape; obviously, many factors besides line count determine the quality and atmosphere of a space, and it's indeed the case that many chats -- such as the EA Corner, MIRIxDiscord, and LessWrong -- maintain a much smaller presence despite being in many ways more centrally 'rationalist' than their more-active cousins.
My apologies for this post being concise to the point of uselessness -- there is a great wealth of other relevant things I've picked up over the last two years of administrating spaces in this area and plan to articulate soon -- but I've got plans this evening and am only able to write up a quick summary right now!
PS: In the interest of full disclosure, I am the founder and proprietor of my 'scord and the 'scord of "LessWrong", which I've linked to in this post.
PPS. I am not sure what the policy is on posting public invite links to certain chats, and the LessWrong discord itself is currently in the process of a renovation, so I have omitted some from this post, but would be happy to update it once I have gained permission from the relevant people.
That said, the Discord section of the diaspora map has gotten pretty out-of-date; a lot of the chats listed have either died, gone dormant or been subsumed by others (or, indeed, have increased in stature greatly through the process of subsuming). I would update it, but I don’t appear to be able to edit the page.
Click the “View or edit this table on Google Docs” link above any of the tables!
I would like to highlight Russian LessWrong Slack, which has 2000+ registered users, ~150 WAU (among which ~50 are posting) and ~80 DAU (~25 are posting).
aisafety.community (now hosted on aisafety.com) has been maintained actively for several years and lists dozens of communities in the space, both online and in person.
Trying to follow this link fails with the following error message: "Closing link: (<omitted>@b.clients.kiwiirc.com) [WEBIRC: you don't match any configured WebIRC hosts.]"
There's The Bayesian Conspiracy's discord server. No need to listen to the podcast or to related podcasts to participate in discussion.
There's https://rationalityeurope.slack.com/ which is a channel for the European community.
In Berlin we have local LW and EA channels but neither is designed for a global audience, so I won't post the link here.
A few times over the past few years newcomers to the community have asked me how they can start engaging with the community, and one of the lowest-cost ways to engage has historically been chatrooms.
I know that there has been a pretty significant proliferation of LW/Rationality/EA-related chat-servers in the past few years, and it seems like a good idea to collate all of them into a central repository.
I know about Elo's LW-Slack, and I know of the abstract existence of a bunch of EA-related Discord channels, but haven't been super active in this space, so I would appreciate other people's contributions.
If we get a good list, I think it would make sense to add that list to the community tab to make it easier to discover (or at least link this question from the community section).