Specifically of the "I need to reach out to this team I don't know about their product" variety.
A) If they interact with Slack, I can search previous answers
B) It promotes a culture of openness. Huge benefit in some orgs! We talk about our projects, warts and all, in public channels. If all your org channels are private, you're definitely Doing It Wrong
C) It's far more scalable than ticketing. Issues can be resolved in three lines of text, rather than ticket creation, queue, assignment, closing, etc.
As an above commenter noted though, you can and should push back on expectations of constant availability. Slack is asynchronous, not for initiating hi-pri issues.
You are describing a proprietary, expensive, intrusive, demanding rewrite of SMTP.
What keeps Zulip threads from exploding in practice? Either on the UI or usage side?
E.g. How to I keep from going from "One channel with a hundred unread messages" to "One channel with twenty unread threads"?
Also, what features exist when a thread diverges from the original topic?
E.g. We were talking about the "afternoon lunch" at the "annual meeting", and then someone mentioned their favorite restaurants in the area, and now people are replying to both?
Organization seems more like a usage problem than a technology problem. Or at least one that I can't see manual categorization solving.
For diverging topics, you can easily edit the topics of the messages that are a diversion to be a new topic. This helps a huge amount when you have new users who haven't learned the convention of creating a new topic when bringing up something unrelated, since anyone can clean it up in a few seconds.
But Slack is certainly easier to install and use (by being centralized).
It's like SMTP, if nearly every conversation went to list-all and our email clients were designed to intelligently allow us to choose what sub-section of the thousands of messages a day are important to us.
Or, like we already knew, it's an expensive, intrusive, proprietary upgrade of IRC.
My experience has been that it goes on for thirty or three hundred lines of problem report -> steps to reproduce -> troubleshooting -> proposed solution -> etc. Two days later someone else gets pulled in so they look at a Jira ticket with an empty description and zero comments...
At some point, a channel should be created for the issue (if long lived) or Slack conversations transplanted onto a ticket.
On the other hand, I've had an equal number of times where ticket formalism led to a misunderstanding, someone on another team taking an incorrect action, and a couple weeks to get resolved.
Work that could have been saved with 10 minutes of direct communication.
Or the dreaded hot potato ticket that out of misunderstanding / laziness gets reassigned to different teams, until a week passes without any actual work done.
So, I guess the optimal solution is to know what each tool is good and bad at, and let those guide actions and policies.
That's been my main complaint about GitHub throughout its meteoric rise. Its public contribution graphs and user profiles littered with hundreds of dead forks certainly encourage this behavior.
And I say this not as a person who has an unreasonable disdain for things like business processes and engineering tools (such as bugtrackers); I tend to favor (good) process more than other people—I've had personal projects where I'm the only contributor and user, and yet if you peek into the bugtracker you'll see hundreds of comments from me explaining exactly what's going on wrt the root cause and any fixes, and all known issues at any given time have an appropriate bug on-file.
But when I use GitHub, it's like every interaction ends up getting sidetracked either due to input from users trying to feel productive by leaving comments that are ultimately value-negative, or some weirdo contributor responding to my bug report as if I'm filing a support request and who then tries to "help" me by explaining how I can work around it (I have no problems working around it—in fact, by the time you're hearing from me, that's old news. But this is a bugtracker! For, you know, tracking bugs!), or the peanut gallery using the bugtracker like it's a phpBB forum dedicated to general chatter and expressions of gratitude related to the project (instead of, you know, tracking bugs!).
The worst is when somebody is showing off a project, I take a look, find something like a simple typo, and let the person know, and then they ask me to file a PR. First, I'm probably not even interested in your project even as a leeching user. Secondly, if you can't be bothered to do anything about this thing in your own project that you already understand that that you probably already have opened in your IDE right now, do you really expect me to clone the repo, poke around until I understand the busted directory structure you're using to organize the code, locate the appropriate source file, commit it, and then use GitHub's needlessly convoluted pull request workflow that involves pushing those changes to a third fork and asking you to review them? Do you understand that all this is happening on top of the assumption that I even have a GitHub account in the first place? Why don't you just Alt-Tab over there and help yourself instead of offloading work onto some random stranger who has no vested interest in your project but who decided to spend a little effort typing out a message that would be of interest to the person currently pimping out their project?
... and then every time I mention this, someone comes around, totally misses the point, and leaves an obnoxious comment that "You don't have to clone the repo! You can make minor fixes like that from the GitHub web UI!"
It's like nobody knows how to distinguish between busy work vs things that are actually necessary to the process and/or indicators of real, forward motion.
Slack is getting such a huge valuation so quickly because it is incredibly simple to use and is very user friendly. IM tools like Skype / Sametime / whatever have been around for companies forever, but Slack is much more user friendly and frictionless to use from the ground up, and with plugins even more useful.
I think most of the hate here keeps coming back to issues with peoples coworkers, not whatever IM platform they want to dislike that is currently making tons of cash.
It assumes that I want to search within a certain channel or messages with a certain person when that's where I'm clicking the search bar from, but I can quickly erase that if desired. Files, messages, and people, are all searchable. It's pretty powerful and extremely user-friendly (most non-techies would have trouble with the syntax for specifying who a message should be from while searching).
Meanwhile, with Gmail, I discovered yesterday that when I'm part of a mailing list attached to an email address (let's say product@startup.com), and I search an email address that was cc'd on the product@startup.com email, nothing comes up. Resulted in a lot of wasted time.
but as i'm starting to learn: nobody really documents things anyways.
Backing up your knowledge store is a very separate task from your day-to-day use of it. It's just as possible to back-up your company's slack messages as it is to back-up the company's wiki.
It's hard to imagine using a wiki for that, but if that's how you do things I guess it's fine. As long as it doesn't rely on people copying their email discussions to wikis manually. Not sure how you'd be alerted by an important wiki update that you need to respond to, though.
"technical conversations I have had with my colleagues where I can go to recover details I might not remember from a month ago. Then again email also does this just fine, and doesn't cost as much."
For static instructions like setting up a dev environment? Sure a wiki is perfect. But I don't use a wiki for technical conversations like "Hey icedchai, I'm getting an error message that the COM port is not detected and I remember you said something about solving it in yesterday's standup. Can you point me to where the fix was?"
That message is better suited for slack or email than a wiki. (Your solution might be in the wiki but I'm contacting you because it wasn't easy to find, or searching for the error message didn't turn it up).
But if I use email, then when we hire a new employee a month later who gets the same error, your answer will be in my records but not theirs.
Another poster suggested a mailing list, that is a good option that makes email viable for this.