I'm a mod on another forum and they get hit with spam like we've seen here. It's an endless game of whack-a-mole, once you block an IP, they use another one.
I'm a paying member here because I understand that it takes resources and money to keep a forum going. That doesn't guarantee 100% against the spam attack that we just saw, just that there will be resources to clean it up and measures to thwart future attacks.