I heard that if a website can get a "do-follow" link, that will help the website to have a solid backlink. If there are many do-follow backlinks from the other website, it will give a good ranking at the search engine for a specific keyword. The website needs to have a keyword to compete with the other website, and if that website can gain more do-follow links, it would affect the rank on the search engine. If you stop the campaign, even if your link is still at the forum, your position in the search engine may be replaced by other websites because they still use the campaign to have more backlinks from the do-follow backlinks from the other websites or forum. But I don't know much about SEO.