I feel your pain.
The internet is an anonymous medium. When people have the opportunity to share text, photos or videos there is always the possibility that a small percentage of users will abuse that privilege.
We deal with SPAM and SPAMMERS everyday. We have several ways of dealing with SPAM and each case is reviewed so we can take the best action to prevent future abuse.
I don't want to talk about our preventative measures in detail, because that may give the SPAMMERS more of an advantage. I will say that banning IP addresses is not always a good choice, because many people do not have static IP addresses.
You can do your part by reporting SPAM to the moderators. In general, links belong in the "Free Sites" forum. You may choose to avoid clicking on links that are posted in the other forums. It may be wise to avoid clicking on links posted by users with a very low post count.
Thanks,