Except these forums have higher standards than that and you should be able to notify people when you're not being serious. People who can't tell don't deserve to know.
Among all the forums I've ever visited (okay, registered at) this one has the lowest standards, but joke tags and serious tags would just make it worse. You can't figure it out when I'm trying to make a joke? Buy a joke book, but don't make me use joke tags.
what we really need is the admins to add tags, and not tell anyone what they are, just that they added them. That would be kewl.
Until someone quotes them and figures it out.
Ooh! I know! Tags that you can't use until you're at a certain post count!