Negative SEO is used to collectively refer to any attempts made to adversely affect the rank of some third-party website. Link building strategies are generally classified as white hat, grey hat and a black hat by Google. Black hat strategies are the ones which are condemned by search engines and the usage of which can lead to penalties or even bans on a particular website. Any competitor which tries to bring down its competition by pointing numerous low-quality links onto a competitor website faces the danger of a manual penalty or even a ban on the website.