I've now changed my actions on anything I perceive as spam. Most of the dodgy posts consist of a poorly-written reply which claims 'this of much interest in me try lose weight', or whatever, then a spam address or two tacked on or in the message. There was also a spate of copy and pasted messages from other forums (I searched the text strings on Google), with similar spam URLs in.
Whereas I was originally editing out any URLs, I've now started deleting whole posts - I hope I'm not exceeding my remit here, but no one else seems to be keeping an eye on things.
I'm thinking it might be an idea to give people a warning when they post like this (thus giving them a chance to show we've got it wrong, in the unlikely event we do), then if they do it again, permaban them. It might seem harsh, but boards soon drown under a flood of spam if you're not careful, and good boards go to the wall as no one wants to use a board like that.
I'm a moderator on a motorcycle related board, and we've had a major battle there with spammers, but with careful message moderation and filters in place to weed out potential spammers as they sign up, we've won the war against them.