[dashwav]

I think that the biggest differentiator between Discord and the others (mumble, TS, Vent, etc) was that Discord has very mature text chatting as a first class citizen, rather than an afterthought. This is what I have anecdotally seen as the primary thing that has made even people who casually voice chat join public discord servers. The model is much more friendly to casual users than either TS or Mumble are.

[cortesoft]

When I was using Vent and Teamspeak you had to actually host the server, as I recall... so someone had to set it up and manage it, or you could pay a third party to do it, but that was always too expensive for my friends and I.... discord is a lot easier to set up your own server and find and discover other servers

[bradlys]

Yep. This is the major differentiator to me and it's obvious why it caught on after that. When I heard about Discord I was like, "Weird, so many people are hosting their own servers or paying to host a server now? Why did it catch on now? More affordable?" Once I learned it was all free... kinda obvious.

[unethical_ban]

"free"

Sure there is Nitro, but I believe data mining is part of the devil's bargain.

[chii]

I agree - text chatting is the first foot in the door. It's non-committal, but gets you the ability to voice chat when you feel up to it.

Things like TS and Vent is voice-chat-first and thus, you will only join _after_ you've made friends to voice chat with online in some other platform (like irc or a game). There's no TS community, since it's purely utilitarian, unlike discord.