Well, it was too good to last. Up until recently, this site hadn't been visited by many spammers. Requiring users to register to post anything helped with that, but certain persistent ne'er-do-wells have spoiled things. So what do I do about the spam problem?

I considered taking the step of approving all new users manually, but I didn't want people to have to wait hours or potentially longer for me to approve them. Instead, I've chosen to install a new module (the very useful user notification module: http://drupal.org/project/user_register_notify) that sends me an email when a new user signs up. This way I can:

1. Check the email they've provided. Sometimes that will tell you if a user is a spammer. Certain domains are almost always spammers.

2. Check the forums. Spammers don't waste time posting spam. They aren't likely to sign up for an account and come back hours later to post garbage. So I wait a few minutes and take a look.

When I do catch a spammer, I block his account. This way, if they still want to spam, they have to go to the trouble of signing up for an entirely new account, with a new, valid email address.