We had some obnoxious spammers on here today, and a couple members were offended. I am in the process of trying to find the best way to combat this. Please accept my apologies while we shore up the defenses!
We're okay with using the signature for photography-related promotion, as long as the member isn't spamming the forum with useless posts to get the signature up in various places, and as long as the signature isn't an eyesore. It's not a very specific rule, but it's stated in our TOS. This has worked well for us at Mu-43, and we've only run into problems with it with two members there.
There weren't any, but that's a good idea and I'll put some rules in for that.
I just made a lot of changes. New registrants now have to answer a question and verify email (unless they register through Facebook), which should get rid of most bots. Also, new members are no longer permitted to email or PM other members using our board until they have at least 3 posts.