Can somebody that likes it explain why it seems to be doing so well?
Discord took off because:
* The message search is much better than free tiers of slack
* You don't need to set up a separate account per server
* It didn't have the user limits of Teamspeak
* It didn't have the ads of Skype
* A big inflection point was Skype launching their desktop client that was basically Web Skype in a window and sucked
* For a server with your gaming buddies, a drop in drop out perma voice channel is really a better model than distinct calls for slack. Also for public servers. And if you want to VC with your friends 1:1, the option is still there.
* Link sharing to invite users to a server vs having to set up a server/bot to give out invites as running a public slack used to require. Also used to not even require an account so was great for that pick up player you found for one night
* For the large server setups, discord's permission/moderation setup is way more flexible than Slack's. Slack basically has admin/not admin. (though discord does need to separate pinning from deleting other user's messages)
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For a summary, Slack is targeted at the business case. In a workplace chat, there should be no need to moderate, since bad behaviour can be taken to someone's boss/HR. And the sign up/multi server flow was not optimised for this usage model as Slack didn't care (at least when I last tried public Slacks, these days the only Slack I use is my employer's).
Discord is actually optimised for consumer use cases, and consequently built up such a network effect that even if Slack did invest heavily in their UX there, would be quite behind.
Free
Able to hop servers/channels extremely easily (for a game it's just hey join this discord server/channel -> click and you're able to start speaking immediately)
Search is good, as it @ing someone to get their attention. Private messages also good
Share screen really easily
The bots are phenomenal. I use it to play world of Warcraft, we have a "raid bot" which is fantastic to organise stuff, and also have several music bots where everyone can hang out and listen to the same Spotify/YouTube playlists at the same time. I'm sure there are plenty of other bots but these two are just what I use.
Inline images, GIFs, videos etc are really smooth, as are reactions/replies
Drawbacks I've found:
App isn't the best. If I close it in the background as I do with most of my apps, I don't get a push notification so if someone PMs me I don't see it until I open the app again to check
Channel notifications can get overwhelming quite quickly, but tbh I'm not sure there's anything they can do about that other than maybe add an option to default mute everything and then only get notifications for what you want on joining a server.
The rest is network effects. If your entire gaming guild or clan or group of friends or whatever is using Discord, you are also using Discord.
If you mean "why is anyone besides gamer groups using Discord?", that is because most gamers are not just gamers, but also people working in day jobs, or open-source contributors, or active in NGOs, or have non-gamer friends with whom they needed to chat lately due to COVID restrictions, or whatever else. They knew Discord from their gaming life, so they just tried applying the tool that they already knew well to the (slightly different) job. With varying success, but with some success nevertheless in some cases.
What an absurd privacy violation.
Not to mention that you can obviously disable this.
Hence if Discord aims at expanding its user base beyond the (multiplayer) gaming community, it should definitely think twice whether to keep this sharing setting enabled by default. At a minimum I would expect them to try to deduce somehow whether you are using Discord as a gamer or in a non-gaming-related setting, and use the suitable default. Or maybe just disable it by default, so gamers who want this feature enabled need to turn it on.
I've known people in office settings automate their IM status (back to at least Lync/Skype for Business before Teams) to say things exactly like "making a presentation" or "busy coding", whether for fun or for micro-managing bosses or nagging coworkers hoping to digitally "peak over their shoulder".
Making it opt-out versus opt-in is maybe "gaming context-related" as Xbox and PlayStation both have opt-out versions on their own social networks. But the existence of detailed and automated status messages certainly isn't new from "gaming contexts".
Don't worry, Discord will!
Not the same as native support, but in fairness, I was being tongue in cheek!
But you can enable it on a per-app basis.
Maybe it's because Discord was targeted towards gamers, and I'm a gamer that had no problem understanding its UI?
If you join more than a dozen servers, yeah it can be a bit overwhelming, but Discord lets you put servers into groups, similar to how phones let you put apps into groups.
It offers a couple of gamer-y features that Slack doesn't like voice channels. But make no mistake, the main reason is because it is free.
There are also a lot of bots you can add for different tasks.
It kind of feels like a realtime social network.
Where it's really lacking is to structure information that should be available to anyone, but I guess that's not what it's meant for anyway
Slack's business model is selling to "the group". The features you have available are what your "admin" decides is good for the group, and upgrades (especially upgrades from the "free layer") need to financed/budgeted as a group decision.
Discord's business model is that individual users are the paying customers so there are fewer features "nickel and dimed" at the group level. If I want better paid features as a user I don't have to convince an entire group to buy into the idea. I especially don't have to convince multiple such groups to do it if I want the same paid features in every group I am a participant in I don't have to convince the admins of multiple groups to pay for them (and/or figure out how to bill for them). Where Discord does have group-level paid features ("boosts"), they are presented as bottom up "collective individual effort as multiplier" more than "the group needs to top down pay a monthly invoice".
From a user perspective, in Slack I'm not the customer, I'm a cog in some wheel that is the customer. On Discord, I'm the customer, and that deeply impacts a lot of how Discord operates including and especially how it treats the "free layer".
Because I haven't. It's a nightmare, you need custom software to even invite people.
Besides that, its severely limited. Discord has a real free model, slack does not.