I think they use the email too. I once made a second with the same email and it was fine for a few minutes and then banned. I hadn’t voted or commented on anything yet.

Then I made another with a brand new email on a different service and it too was banned pretty quick before I engaged with anything. That one I think was fingerprinted because my home IP changes every couple months naturally, so I wasn’t on the same IP that would have been banned. Also sometime around then I started using a VPN and it was still banned, so I’m thinking it was a fingerprint.

At that point I was kinda over it but I was curious about the system. So I tried once more with another new service email, on a different IP from being on a mobile away from home. That one worked. It probably still works, but I don’t remember it or the password or the email I made for it. So it’s out there somewhere, but I don’t care any more because this all finished up around the time reddit killed third party apps, so I found this and my app came over, so I just entered the fediverse.

I still have my NSFW account there which does still have all of my niche interests in far greater supply than I’ve found here so far. I’ve got my NSFW account here, but all the communities die pretty quick, so it’s not much use yet.