A few internet sites (other than Numista!) that I frequent, to recommend.

Just like real life hobbies, I'm sure none of us are uni-dimensional Numista users; if you have access to a computer you probably also use it for things other than Numista as well! Everyone's got a few favourite sites they frequent other than the usual Youtube, so I thought I'd share a few of mine here.

Duolingo: https://www.duolingo.com/
This one's a language learning site and forum that's been mentioned previously before; you basically work through levels on a tree, and set a daily goal for yourself (e.g. 10 XP per day means you complete one "lesson" every day). Currently using it for Italian and Spanish, although I also have an aborted German course I haven't touched in months now.

Sporcle: https://www.sporcle.com/
This is a trivia site, where you can test your general knowledge on literally anything, from history/geography to literature and pop culture. Very fun way to spend a slow weekend at home, and improve your general understanding of the world we live in.

Quora: https://www.quora.com/
Another general knowledge site, but one for reading rather than anything too interactive, great if your wrist gets tired. I usually frequent the history and geography sections, and I've even written a couple of basic answers, but have no time or energy to become a fully-fledged writer there.