Is this true for Rust?
See:
Most of the compiler folks have their zulip server.
Community hangs around here
The Rust Programming Language (this one has 30k). I personally like this server, beginners section is awesome.
Rust Programming Language Community Server (this one has 20k)
Just to be transparent, your messages on Slack are not Transient nor disappearing from storage. I can go back right now and pull up all history in public channels from any time period I want (via the slack history download feature they support). I am also pretty sure this is not restricted to just Slack admins.
So maybe don’t let loose too much : )
For the nonprivileged user my understanding was there is a 10k limit on messages. If that’s not true then - yea there’s not much value in having a slack imo. It’s fine for moderators to be able to access all of the chat history. At the end of the day - it’s a programming language chatroom.
One thing I have wondered about is whether moderators can read other people’s direct messages.
People mentioned in another thread that including slack questions in search results on Discourse would clutter up the search with junk. That could be. But couldn’t there be a checkbox when searching to include vs. not include slack questions.
Also couldn’t some sort of machine learning method determine which slack stuff is a coherent, contiguous question-and-answer series of messages (thus worth including in search) and which is junk? Maybe that’s too complicated.
And you can build a great library by Bookmarking!!
One thing that’s now implemented in Zulip is optional transience of messages. We can set streams to automatically delete messages that are older than some cutoff.
I don’t think we’re using this right now, but it’d be reasonable for us to make a #random (transient) stream or something if people saw a lot of value in that.
I think it’s good that discourse is visible to anybody on the internet, without login. That’s why I chose to answer makie questions here instead of zulip. Over a longer time frame, this helps a lot when googling makie (or Julia) questions and leads to better visibility overall
This feature is coming to Zulip soon 
The idea will be that we’ll be able to mark streams as public and then people can view those specific streams without logging in. Currently, we are just bridging the #helpdek (published) channel like so: Zulip Chat Archive but will transition to a public stream when that’d possible.
I use Discord, Slack, Zulip, and Discourse. Unfortunately, I do not have 4x the time and so I’m juggling among these. Knowing who’s active on which platform is useful – e.g. if I want to ask a question and I know @Mason may have the answer then I get on Zulip 
I actually spent some time and compared these communication platforms before at my last job. It really boils down to the following spectrum:
Chat <----------------------------> Forum
From left to right, I would place each platform as such:
A chat platform encourages real-time communication. Conservations tend to be more casual. And, it allows people in the community to build relationships more easily. By contrast, a discussion forum promotes longer form of discussions, which typically requires more thoughtful responses (like what I’m trying to do here at this moment).
Slack’s threading model makes it possible to focus on a single topic in the thread. Zulip takes it further by requiring every conversation to be a thread. That’s why they sit in the middle.
Without threading (like Discord), people more or less follows a conversational style of communication. When you get on a channel, you probably just catch on to the latest and usually not worry about the history. In Slack, I am tempted to scroll up and read what I missed because it’s easier to do so with threads.
Personally, I found Slack’s model most satisfying – with the exception that disappearing messages is occasionally annoying.
@anon92994695 mentioned earlier that we have an active community on Discord. It’s called Humans of Julia and I happen to be the admin/mod there. Just some stats:
One nice thing about Discord is that you get audio/video conferencing channels for free. We have several community projects going on at the moment, and we do use it for our online meetings.
What happens is that people tend to use whatever most convenient to them.
I’ve heard from people wanting to use Slack because they are already using Slack for work and with other communities. The same can be said for Discord and Zulip. For that reason, trying to force everyone to use the same platform isn’t practical, and we would never be able to do so.
Just my 2 cents.
It’s nice that Zulip has infinite chat history, but are we confident that will continue to be the case 5 to 10 years from now?
(Disclaimer: I’ve never used the Julia Slack nor the Julia Zulip.)
Zulip is open source. If they change their minds about providing free infinite history to open source communities, we could just switch to self hosting if we really wanted / needed to.
I’m not trying to play devil’s advocate here, just curious. In the event that they change their minds about providing free infinite history, perhaps they wouldn’t be willing to transfer the existing history to the Julia community? Or is there something in the license/contract that says that Julia owns all the data on the Julia Zulip?
I talk to them semi-regularly on their own Zulip instance, they’re pretty kind responsive people who I doubt have reason to try and hold our data hostage.
If we decide we really want to be paranoid about this, I can just set a bot to auto-export all the (public) chat history 5 times a week I guess.
Since no one has mentioned it yet, I will say that I wish Julia relied more on StackOverflow. I know it is a for-profit company but the voting system there works and it is a great way to prevent duplication of questions. I know discourse has a similar mechanism, but the SEO for stack overflow is really good.
In terms of getting basic information, out-of-date, pre-v0.6 StackOverflow questions are often the first answers that come up in google searches. 
As a simpleton who can’t use git properly, it’d be best if the Answers were on stack overflow, so I could just google them and they come up normal like in R, Matlab, Mathematica, Bash, Python…
Still we just have to accept this wonderful community wherever it is. We aren’t going to pick up and move this whole caboodle. Just know that answering Julia questions on Stack Overflow is the path of the rightous.
For what it’s worth, we are on a good path as far as stack overflow goes. It’s a long game but our presence there has picked up over the last couple of years.