Google has made a massive algorithm update. Though the updates are regular, this time it is a massive one affecting almost 11.8% of the queries. Content farms are pages which have low quality content. Automated softwares which get content from other sites & post it in a page. Google has launched a war on this & has updated the search results. This will help increase the rankings of the sites with original & high quality content. This is initially launched in US & will be implemented globally overtime. This is an important step towards providing high quality search results.