Some small instances are seeing sudden increases in numbers of registered users (4k to 5k new users) but not an equivalent growth in activity, my guess is someone is creating accounts on instances without captcha enabled for account registration. Most of the top 10 fastest growing instances shown here fit that criteria.
Odo
joined 1 year ago
home of the largest lolicon community
yikes
I guess that's possible. The instances I mentioned look like this:
https://fedidb.org/network/instance/parapheum.com
2 posts, 1 comment overall.
It had 10 users two days ago and 4.6k today, not a single one of them seems to have posted or commented.