What is Google Panda?

Google Panda is a change in the algorithm of Google that was published in the United States on February 2011 and Europe on April same year. For it's launch it affected more than 12% of all search results

Successive Panda updates have placed greater emphasis on improving the recognition of the relevance of a website. Panda has penalized sites that copied content from third parties, which did not provide real value to the user, who had excess advertising or navigation hindering user to generate a greater number of page views.

The best with Panda is to be sure of your own content, that is completely original and adds great value to your user, that you keep your website updated or even looking for new formats to enrich your contribution to the user. More actionable metrics in this case will be bounce rate per page, the CTR in your search results, the time spent and the number of page views.

If you're not sure if the content you already have, a full revision of the generated content never hurts.