Have you tried a modern forum, like Discourse? I'm trying to understand why many open source projects opt for chat platforms instead of a forum. Why are you resignating public and search engine accessible discussions?
Discourse is also very wasteful of space for anything but long-form prose: a single line of text is 180px high (in other words, a typical screen will never under any circumstances fit more than five comments on the screen at a time), and a single-line quote from someone else adds 80px. Compare discussions here on HN with Discourse. I’d much, much rather work here. (Yes, their purposes are somewhat different, especially as regards ordering; and applying the HN structure to longer-term discussion would require changes of some form, because it wouldn’t work if you just took it verbatim.)
If I had infinite time, I’d write a leaner frontend for Discourse with much less magic and much less wasted space.
Public web archives are a goal, and either we'll deploy a bot to publish them, or I've heard rumors this feature may be added to Zulip itself.
In the meantime, it's kind of nice not having everything immediately publicized. We've had (knock on wood) exactly zero problems with spam users, even though it's open to everybody with a Github account. I'm also (if temporarily) enjoying the freedom to talk a bit more intimately, for example I'm discussing a major project I'm considering taking on.
One thing I'd be interested in feedback on is how folks would feel about an ugly/janky version? There's a few different versions we've talked about:
* Being able to use the main Zulip user experience, with "public user" data (no unreads, can't send messages, etc.). This would be best as an actual browsing experience.
* Having a totally new webpage that's mostly just HTML+CSS (better for search engines) similar to our digest emails.
Possibly we'll eventually do both, but I'd love feedback on which of these open source projects care about the most.
(In any case, it'd be configurable at the stream level, so you could have some but not other streams that are public in the organization be publicly archived; we already have the data model for doing that).
For people who actually want the Zulip experience, I have no problem just asking them to sign up for real. Since we have open signup based on github login, it's a pretty small barrier.
It's often better to have both, I think.
the best will be chat+forum, and support mailing list style digest, also support post-by-email