Checked the fediverse observer and I see a lot instances with barely any activity skyrocketing to the top of registered users. I can only surmise they're being flooded with spam accounts and haven't noticed.
Example: https://cubing.social/
How much should we worry about this? Should we be taking pre-emptive steps to defederate them to avoid those spam accounts being utilized against the threadiverse?
The spam problem is already on our doostep and we need to seriously start considering how we're going to handle it ASAP. We need to take knowledge from how email dealt with it and find ways to quickly distribute knowledge about spam instances.
You could either outright defederate now or wait until possible spam starts and then defederate it. The community at large might want to maintain a list of bad instances.
The problem is probably similar to email spam. It's not easy or fun to deal with.
The problem is that lemmy by default provides little support for anti-spam measures, and makes new communities allow open registrations by default.
Lemmy will have to eventually add anti spam features or it may end up getting eaten alive by it. Else, the only option is to rate limit signups, which is bad because that will limit new legitimate users.
Email and usenet are full of spam, and there is nothing fundamentally different about lemmy than email.