quality results of the search. The reduced quality and rapid creation of articles on such sites has drawn comparisons to the fast food industry and to pollution: Reaction of search-engine providers In one of Google's promotional videos for search published in the summer of 2010, the majority of the links available were reported to be produced at content farms. In late February 2011, Google announced it was adjusting search algorithms significantly to "provide better rankings for high-quality sites—sites with original content and information such as research, in-depth reports, thoughtful analysis and so on." This was reported to be a reaction to content farms and an attempt to reduce their effectiveness in manipulating search result rankings. The privacy-focused search engine DuckDuckGo does not show results from content farms. Research Because of their recent appearance on the web, content farms have not yet received much explicit attention from the research community. The model of hiring inexpensive freelancers to produce content of marginal or questionable quality was first discussed as an alternative strategy to generating fake content automatically; this was discussed together with an example of the infrastructure necessary to make content-farm-based sites profitable through online ads, along with techniques to detect social spam that promotes such content. While not explicitly motivated by content farms, there has been recent interest in the automatic categorisation of web sites according to the quality of their content. A detailed study on the application of these methods to the identification of content farm pages is yet to be done. See also Churnalism Click farm Google Panda, a change to Google's search algorithm that is intended to filter out low-quality sites Link farm Search engine optimization Scraper site Spamdexing User-generated content References Digital marketing Online publishing Search engine optimization