Look up the origins of IRC's EFNet, which was created specifically to exclude a server that allowed too-easy federation and thus became an abuse magnet.
What's the requirement to become federated? Say someone starts their own server, are they able to load it with bots prior to federating then suddenly go online and fuck shit up before they get defederated?
I guess what I'm asking is there action needed by every instance before they are federated with a new instance. Do the admins of each instance have the opportunity to do their due diligence before federating with someone or is it automatic?
Yes, people still use it all the time. More people use IRC day to day than they do Lemmy at the moment. Though Lemmy's numbers are close without the bots. Lemmy will overtake IRC soon if it's not already. I've got a v3 IRC client right here on my desktop.