Also a way to harvest personal data and passwords, and drive traffic to instances.
New users tend to register with the busiest servers. So, start your own instance, flood it with fake users to get to the top of the rankings. Tweak Lemmy to store passwords instead of hashes. Allow open registration, sit back and wait for people to sign up with their emails and potentially-reused passwords.
Ranking instances by number of users drives undesirable behaviours all-round.
But that goes with every service on the internet with accounts ;-) It would always be best to run your own if you can but I certainly can imagine not everyone can do that so trust is also a big factor
Luckily there's more than just total users that make up the stats for an instance so it's a little easier to evalutate and chose I guess
I guess this is a potential disadvantage to decentralization. With a centralized site, the owner would have a vested interest in the security of the site because culpability for stolen passwords or other nefarious things would fall back to them. Here, with a decentralized model, instance owners can manipulate the particular instance to not match others and do nefarious things. Up to now I had only heard of the benefits of decentralization and hadn't thought of this. Food for thought perhaps. All it takes is a few or even one nefarious instance (if its bad enough) to spoil the general public's thought on this model.
There's a lot of BS accounts tallied from BS instances in the user counts. The bots are coming out in force. If that was a million actual humans that would be pretty impressive. But still there's a lot of real people and growth is big, but the total user stats are misleading. Looking at comment and post counts provides a better idea, it's about doubled since the beginning of this month. Still nothing to sneeze at.