Magazines (kbin) and Communities (Lemmy) are the naming conventions for the group type of posts offered - like subreddits. Magazines and Communities are effectively the same thing, just different naming conventions from their different backbone software running on the instance.

Instances are the full server in which the communities and users are held. Like sh.itjust.works is an instance - it’s the page where you can log into in order to then interact with anything both housed within your instance as well as the greater fediverse (barring any defederated instances, as you mentioned).

I’m subscribed to 50 total communities / magazines across Lemmy and kbin and honestly, almost every time I hit refresh (while using subscribed and sort by new - I understand there are some front page bugs) I get new stuff to read or look at.

I haven’t felt like it’s dead here since I signed up and the engagement has just gotten better as people get more comfortable with whichever software they’re using (either Lemmy, kbin, or even Mastodon). It’s not an overwhelming amount of posts like trying to read Reddit by New.

And I look regularly for other communities I might be interested in.