What does Content Farms mean?
Making money from getting large numbers of visitors and then hoping some of them will click on some adverts is the basic idea behind content farms.
To do this they need to generate large amounts of text written in a search engine friendly way in order to get ranked. Search crawlers like Google can spot computer generated work most of the time so search farms will pay freelance writers a few dollars per article.
The idea is to create pages which are 'just good enough' for search engines to index and then also gain rankings by the sheer scale of the overall content.
The issue has been that this squeezes out genuinely good content just because it has not been optimised or does not reside on a website of the same size.
From early 2011 Google has been actively working to identify content farms and reduce their rankings.
What actually constitutes a content farm can be debatable. Ezine, a site that hosts articles submitted by internet users, could be seen as a content farm as it does not check the accuracy of articles in any great detail. eHow has also been mentioned by some as a content farm because its' articles are genuinely shallow (lacking detail) compared to other source of information on the net.