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.