Discord is a java app or something, it's a chat app used by many different breeds of people :D

a lot of people on steem are using it as a chat alternative to the rocket chat endorsed by the main dev team.

you can run it on the browser or on the desktop, even mobile, because the java is supported and runs on it's own virtual machine I suppose, newb as I am I don't want to confuse you any further :D

If you have questions feel free to ask away, be it about steem, steemit, busy, chats or whatever :)