Google has introduced two SEO policing updates known as Panda and Penguin. Both of them had the same purpose of lowering the rank of low-quality websites, and increasing the rank of higher-quality sites.
Panda looks at the content of an entire site (or a specific section of a site) has any impact on search rankings, as opposed to just individual pages. If a significant number of pages on a site are flagged as having terrible content, the whole site can be penalized.
Panda basically prefers unique, original content; particularly content like in-depth research reports or analysis, over auto-generated content. For websites looking to improve their rankings, they should separate out and get rid of all of that content with little or no value so that shutting down the entire site can be avoided.
Ultimately, Panda is trying to weed out duplicate, overlapping or redundant content that isn’t beneficial to the searcher. Mostly, it aims to take down so-called “content farms,” which publish a lot of low-quality articles stuffed with popular keywords to drive traffic and to get links. It also works to stop content scrapers from outranking the original author and content.
Penguin specifically is cut out for webspam. With this update, any sites that are found to be violating Google’s webmaster quality guidelines can have their site rankings dropped.
There are a few major offenses that Penguin was designed to combat, including stuffing sites with keywords (particularly low-quality keywords), cloaking, spamming anchor text, purchasing links and more. But even some less obvious techniques could wind up on Penguin’s radar, such as incorporating irrelevant outgoing links into a page of content.
Google says Penguin does much more than a white hat SEO and is looking out for sites engaging in webspam tactics to manipulate search engine rankings.
If you’re having a Penguin problem, the best way to start recovering your rankings is by getting rid of your low-quality links and removing any keywords you may have stuffed away on your site. Basically, anything on your site that may toe the line and appear to Google as a black hat SEO tactic should be immediately removed.
However, Google will notify you on your Webmaster Tools account if it finds questionable links or other issues with your site. You can constantly check Webmaster Tools account and immediately fixing those problems should help to prevent your site from dropping in the search rankings.
You may note that Panda and Penguin are algorithm updates, and the penalties that they enforce are not manual. So you can’t correspond with Google with a reconsideration request to get your site back in the search rankings. Instead, you have to make necessary changes and fix your site on your own, and then wait for Google to come back and re-crawl your content.