If someone has less than 20 posts, they should not be able to post links. Bonus points if it's a shadow blocking where no one sees it except the poster.
Maybe require a captcha to post something with a link if you're under 100 posts.
They're not targeting your users. They're targeting to increase the page rank of what they're spamming. This helps them quite a bit, but it'll also damage MMORPG.COM's page rank by those links being on the site AND having been reported by other webmasters/Google's automation.
Practice doesn't make perfect, practice makes permanent.
"At one point technology meant making tech that could get to the moon, now it means making tech that could get you a taxi."