Why dont you simply not allow a Guest to start a topic or add an attachment. If they sign in to an account have lower post ranking approved attachments and/or topic creation. I doubt a 100 post member would become a spammer. Food for thought.
lol Slozo. Just like Alex 116 I also didn't notice that this is a thread from early in the year. Overall our mods do a good job and do so on a volunteer basis. It is understanable if they aren't always able to get here first thing in the morning. I had just assumed a moderator hadn't yet been chosen. Sorry Slozo.
Did you hear about the retired proctologist? He spent 40 years saying "what's a place like this doing in a girl like you?"
As a member of the computer science / web development community, preventative measures will only work up to a certain point...
How about to start a topic (or even to reply to a topic) the poster has one additional step -typing a word that appears as an image.
Any spammer worm etc will not be able to do that and it adds a couple seconds to each post at most which I feel would be worth it to save everyone some hassle. (Of course that doesn't prevent human typed spam...)