Actually, the true killer feature for discord back in the day was something much dumber, but still heavily related to on-boarding and community transference.

You could join a discord server with a single link.

Account creation could come later.

Considering the competition at its heyday was Teamspeak or Skype, the mere fact you could just actually see the hell you were getting into without some stupid ass "Hol' Up!" instantly made it popular with basically everyone who didn't even know what it was.

My account is dated June 2015 which is apparently a month after it launched, and both me and every single one of the early adopters in that channel that is still up to this day have this same story to tell. We used it because we didn't even have to login at all in the first place when we first got it.

The killer feature of discord was always "open this link for our guild voice and let's go into the dungeon". And this is a brand advantage: you can try that with self hosted tools but discord "feels safe" to click.

The only thing TeamSpeak has on it is multi level voice for complex command chains. But you pay for that with enormous sign up friction.

There's no viable frictionless chat alternative. Maybe jitsi. And if you try to make one? You'll get regulated and have to do the same thing.

> being able to join many communities from a single login.

That's one of the features I hate most about Discord, the difficulty of having separate identities in separate places! You can set a "display name" for convenience, but everyone can see your root identity.

Yes, it like reddit is a community of sub-communities.

The whole fediverse wants to offer that, but I have no idea why single sign on fails mostly to make waves for them. Perhaps it is just user adoption, or technical complexity about privacy protection vs. ease of use.

What is your greatest UX concern that you would like to see fixed?