GOOGLE PANDA VS. PENGUIN

Each time Google rolls out an update or refresh of their infamous Panda or Penguin algorithms, SEOs go wild. Anecdotal stories and panic spread like wildfire across blogs, forums, chat rooms and social media networks. The impact of these updates is measurable on individual websites simply through analysis of web traffic.

Google Panda is a change to Google 'search results ranking algorithm that was first released in Feb. 2011. The change aimed to lower the rank of "low-quality sites" or "thin sites", and return higher quality sites near the top of the search results.
Google Panda affects the ranking of an entire site or a specific section rather than just the individual pages on a site.
In March 2012, Google updated Panda and stated that they are deploying an "over-optimization penalty," in order to level the playing field

Penguin algorithm which released in April 2012 put tighter guidelines on website optimization and adjusted a number of web spam factors, including keyword stuffing, cloaking, unnatural links and content spinning.
Contrary to popular belief, Google’s goal isn’t to run wild with algorithm updates and penalize every site until there are only 10 decent sites left. Google just wants to make the web a better place, and it does that by rewarding people who do things right.