Could you tell me about what is panda and what is penguin and what the deference between panda and penguin?
A panda is a bear that eats bamboo and is native to china and penguins eat fish and are birds that cannot fly but swim instead but info on Google Panda and Google Penguin can be found on the trusty old font of all online info Wikipedia > http://en.wikipedia.org/wiki/Google_Penguin http://en.wikipedia.org/wiki/Google_Panda
Panda went to penalize thin websites. Meaning obvious affiliate sites, site that had alot of keyword stuffing and crappy on page SEO. Penguin goes after poor link building, such as low quality comment and profile links, as well as people that over optimize their links. So if you have a dog training site and all your anchor text says "dog training" that is bad, and you will get a penalty for it. There are other components to it but that is the gist.
These two are the recent high voltage update form Google. Panda update is for the low quality websites in terms of content. This algo is designed to find out such sites with duplicate or crap/spun content and reduce there authority in Google SERP. While Penguin is for the site that have achieved low quality back links through some SEO process that are not thematic and sitewide.
The Google Panda takes out low-quality sites/pages. The Penguin does the same but it focuses on low-quality sites that are keyword-stuffed and full of ads. Hope that helps. Have a good day!