What is Panda and Penguin?

[Paul]

Panda and Penguin are two algorithms used by Google to detect spam.
Panda algorithm is to detect Low quality sites. It means that sites which have very low quality content, thin content, copied content, content which are aggregated from different other sites and manipulated only to get well ranked.
Penguin algorithm is to detect spammy links of a site. It means sites which are using black-hat seo to get ranked in google. This includes links from irrelevant sources, low quality links, paid link sources & also these apply to the links which are outgoing from your site.