What is Link Farming?

[VPSnet]

The idea behind link farming is to increase the number of sites that link to yours because search engines such as Google rank sites according to, among other things, the quality and quantity of sites that link to yours.

[Raj Sharma]

A link farm is a website or a group of websites created only for the purpose of increasing the link popularity of another site by increasing the number of incoming links. But this is not considered a good method in SEO (Black Hat  trick) because search engines such as Google consider link farming as a form of spam and have been implementing procedures to banish sites that participate in link farming. So it's better not to use this method for business sites who are well established.

[Rakesh01]

The idea is to manufacture a large volume of inbound links through interconnected websites rather than earning them naturally. It may temporarily boost domain authority metrics and rankings, but the links have little trust or topical relevance.

If your strategy depends on link equity from obvious link networks, expired domains, spun pages, and manipulative anchors, you're gambling with the entire domain.