In the context of the World Wide Web, the term content farm is used to describe a company that employs large numbers of often freelance writers to generate large amounts of textual content which is specifically designed to satisfy algorithms for maximal retrieval by automated search engines. Their main goal is to generate advertising revenue through attracting reader page views.
I think that Google does not put much emphasis on, or even claim to be estimating the “Quality”of various content in developing its rankings. To the contrary, the focus appears to be on “relevance” and a few other concepts like “timeliness,” and “diversity”.
Content farm is a site that scrapes content from other sites and slaps ads against it. Demand Media meanwhile has an army of freelancers who create original content that they put ads against.Content farms on the other hand look much more legitimate. These are big and oftentimes massive sites which contains all sorts of information. The sites which got rewarded were the sites with high quality unique content and the sites which were penalized were the sites with low-quality or spammy content.
Context Farm is a technique where the Website either copies the content or submits a large amount of contents which are of very low quality in order to attract some traffic for the website at the same time rank higher in SERP's.