Not a single student preferred mastodon from discord. Anyone has a link to an introductory article which could show why it's better to use mastodon? I know mastodon is more like twitter replacement, but still...
This is Mur 
@szopen
1) Discord is very different from Mastodon as it is focused on real time chatting which also includes VoIP and video chatting. Beside it is a mainstay for communicating with each other during the play of multiplayer videogames. This is also why young generation is very much into discord.
2) Mastodon/Fediverse is highly populated by nerds, developers as well as people who hate big tech which basically means that a lot of people here have a relating niche or ideology. It's not a place everyone will like, also being open-source and federated isn't much of a cool stuff to everyone.
@szopen
Though as a professor you can always make mastodon compulsory 
@szopen A more comparable platform would be the Matrix ecosystem (element.io is the 1st party implementation if you want to try it out).
@szopen I think you could do better with matrix compared to discord. Mastodon is really an apples and oranges situation.
@souldessin My problem here is not really a choice of application, because for most purposes we have the home-made solutions. Initially I was rather thinking about encouraging students to use open-source, distributed social media rather than proprietary alternatives. I guess this was wrong approach, since you can't really advocate use of Fediverse by encouraging its use in context for which it was not designed.
@szopen Discourse and Matrix are far more impressive when it comes to productivity.
@szopen im not sure we are even talking about comparable things here.. discord is for voice chatting in my mind, mastodon is for text based social media updates.. similarly one is more about realtime chat the other is more about statuses.