Worth noting that when What died, ~4 new sites popped up immediately and invited all the old members, and everyone raced to re-upload everything from What onto them, which was actually pretty effective. At this point, RED and OPS have greatly surpassed What in many ways, aside from some releases that never made it back (you can actually find out which releases used to exist because What’s database was made available after its death). Users and staff are a lot more prepared if it happens again, e.g. keeping track of all metadata via “gazelle-origin”.

If by “in” you mean how to get into them, generally you’re supposed to have a friend invite you. If you don’t have anyone you know on private trackers, you’ve gotta get in from scratch. Luckily, RED and OPS both do interviews to test your knowledge on the technicals of music formats, though I’ve heard RED’s interview queues are long and OPS’s interviews are often just not happening: https://interviewfor.red/en/index.html https://interview.orpheus.network/

Alternatively, you can interview for MAM, which is IMO the best ebook/audiobook tracker. They’re super chill and have a very simple interview e.g. “what is a tracker”: https://www.myanonamouse.net/inviteapp.php. After that, you can just hang around there for a while until you can get into their recruitment forums to get invites to other entry-level trackers, and then on those entry-level trackers you can get recruited into slightly higher-level trackers, and so on, and eventually RED/OPS should be recruiting from somewhere.

This can feel a little silly and convoluted, but I guess I’d just appreciate that these sites put the effort into conducting interviews for new people at all, since the alternative is that you will just never get into anything without a friend. Reddit’s /r/trackers wiki is unfortunately one of the better places for information about private trackers if you want to do further reading.