Gaming

I hate how discord has replaced this forum culture in many places for this reason, but overall it's incredibly good for participating in communities in real-time, especially smaller ones. I agree with the forum part, but aside from that it has also replaced IRC, Skype/MSN/ICQ, TeamSpeak, etc. all in one place, while even expanding on their features. It's unbeaten for friend groups or smaller communities to create a space just for themselves that features text chat, voice chat, screen/video sharing etc.

Unfortunately though the open source alternatives, even the ones trying to be fully compatible with discord, have not yet reached this featureset and usability level. Also one big issue with communications tools like this is they rely heavily on adoption. Doesn't help me when I can convince my closest friends to switch to Matrix for example, when there's so many more people that I interact with on a daily basis through discord who I have no control over. Especially when the alternative just doesn't cut it for all these normies who don't understand the implications of big companies controlling such exclusive spaces.