Once upon a time, Usenet was THE reason I was connected to the Internet.
These days, Usenet is a mere shadow of itself but many of the purely technical newsgroups still survive.
Because I am an 8-bit CP/M enthusiast, I obviously subscribe to comp.os.cpm, but I also subscribe to some 'newer' active newsgroups like alt.os.linux.mint, and comp.os.linux.misc.
Unfortunately, the other eight newsgroups I am subscribed to might have only one or two posts per year, if they're lucky.