Most of the forum spam that gets posted has links to certain companies/products. Often times these companies are not even aware of what's going on, because they've hired "marketing specialists" to help with their SEO, when in reality, all these guys do is run spam bots. Unfortunate fact of life.
A while ago there were a bunch of posts by one of these bots ("mark1011") with nonsensical posts and links in the signature to twistyride.com. I took a few screenshots, and sent a bitchy email to the guys over at Twisty Ride just over a week ago. Got an email back from them today saying that they're looking into the issue and will talk to their marketing company to ensure this does not happen again. Hopefully that'll result in one less spam bot targeting BCSB.
tl;dr: get in touch the "source" of the spam-links if you want them to stop.