A link farm is a website created for the sole purpose of boosting another website’s SEO rank. The objective of a link farm is to create as many links as possible to a destination page from various pages of the link farm. Backlinks such as these can affect a page’s rank.
However, link farms are expressly prohibited by Google and other search engines, as they’re an underhand and inauthentic method by which to boost a certain website. Search engines that identify link farms will penalise the farm by deindexing them. The beneficiary website, meanwhile, will also have their rank reduced. In some cases, the beneficiary will also be deindexed.