Google released a series of algorithm updates called Panda with the first appearing in February 2011. Panda aimed at downranking websites that provided poor user experience.
And in January 2012, so-called page layout algorithm update was released, which targeted websites with little content above the fold.
The strategic goal that Panda, Penguin, and page layout update share is to display higher quality websites at the top of Google's search results. However, sites that were downranked as the result of these updates have different sets of characteristics. The main target of Google Penguin is spamdexing (including link bombing).
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