Users-per-month is only the count of users who created lemmy accounts on monyet.cc.
Registered users includes users who have visited from federated sites. I’m not sure what triggers the “registration” - I suspect just viewing one of our subs is enough, since we aren’t seeing any major volume of upvotes or subscriptions
For our first day we also had a problem with someone running a bot account creation script. I added a captcha and it went away. At some point I’ll probably purge these. (Not sure how many)
Oh yeah I looked into that.