Negative link building is negative SEO practice which consists of making a massive and brutal backlink blast to create low quality links pointing to a competitor’s website. The process of negative link building aims to provoke a sanction from Google against the competitor website.
There are a lot of fantasies and myths about negative SEO and even more since the Internet advent. Nevertheless, the practice is probably very rare. Indeed, the effectiveness of the process has not really be proven at large scale and if it fails the new links could favor the competitor’s ranking.