Rolled out on May 20, 2014, the latest Panda algorithm update is designed to boost sites with great-quality content, while pushing down sites with thin or low-quality content in the search results. Given that there have been so many minor tweaks to the Panda algorithm, the buzz around the algorithm has been relatively low from both Google and webmasters alike for some time. Both the number scheme (4.0) and the vocal announcement suggest that this is both an algorithmic revision and a data refresh. Ultimately, it’s a major update that lays a foundation for future updates.
The big announcement? It came straight from Matt Cutts via a tweet:
Who is affected by Panda 4.0?
The Panda algorithm is preventing websites with low-quality content from being served in prime placement in the SERPs, and has impacted 7.5% of English-language query results to date. Most visibly, it has wreaked havoc on some very major sites, such as eBay, which lost 33% of its organic traffic . “The winners’ list features sites that publish original, useful or interesting content,” according to Business Insider.
But Google couldn’t make it too easy on us. Just days before the announcement of the Panda update, Google rolled out Payday Loan 2.0, the second installation of an update intended to target a narrow set of spammy queries. While it is not frequent that search engines will release two algorithm updates simultaneously, when they do, it makes it challenging for webmasters to identify the root cause of changes in performance.
How do you prevent being penalized by “the Panda”?
The beauty of Panda 4.0 is that it truly intends to reward great content. Between Hummingbird and Panda, crawlers are parsing content in a more intuitive method, not just scanning keywords, but looking at the intent and focus of a page and how it relates to what people are searching for and talking about. “The essence to crafting powerful content is to write about what people really want and enjoy, and then the search engines will follow,” says Benu Aggarwal, Founder and CEO of Milestone. “For us the art of SEO has always been in the language of people not technology.” So, what can you do? Write high-quality content that engages the visitor and provides them with the information they are seeking.
 and  http://moz.com/blog/panda-4-payday-loan-2-and-ebays-very-bad-day
Source: Paid Search