Google Panda is change to the Google’s search results ranking algorithm ,It was first released in Feb 2011. The change aimed to lower the rank of “low-quality sites”, and return higher-quality sites near the top of the search results. CNET reported a surge in the rankings of news websites and social networking sites, and a drop in rankings for sites containing large amounts of advertising. This change reportedly affected the rankings of almost 12 percent of all search results. Soon after the Panda rollout, many websites, including Google’s webmaster forum, became filled with complaints of scrapers or copyright infringers getting better rankings than sites with original content. At one point, Google publicly asked for data points to help detect scrapers better. Google’s Panda has received several updates since the original rollout in February 2011, and the effect went global in April 2011. To help affected publishers, Google published an advisory on its blog, thus giving some direction for self-evaluation of a website’s quality.
Google Panda was built through an algorithm update that used artificial intelligence in a more sophisticated and scalable way than previously possible. Human quality testers rated thousands of websites based on measures of quality, including design, trustworthiness, speed and whether or not they would return to the website. Google’s new Panda machine-learning algorithm, made possible by and named after engineer Navneet Panda, was then used to look for similarities between websites people found to be high quality and low quality.
Many new ranking factors have been introduced to the Google algorithm as a result, while older ranking factors like PageRank have been downgraded in importance. Google Panda is updated from time to time and the algorithm is run by Google on a regular basis.On April 24, 2012 the ‘Penguin’ update was released, which affected a further 3.1% of all English language search queries, highlighting the ongoing volatility of search rankings.