I was hoping those 5595 spam communities a disgruntled lemmy.world created had finally been deleted, but it's not that.
The data is published about 4 times a day, and there's a bit of variance each day, but not as much as the latest difference.
I wonder how many of those instances are single user instances and the numbers going up and down so sharply are curious people spinning up instances, getting bored and killing them once they get bored. I'd like to be able to see how much other platforms in the fediverse fluctuate
The instances on the list are only ones with communities on them. The website is currently showing 1251 instances for today, so I assume that includes single-user instances