Google Updates Penguin with real time crawling and trying to improve their search results than before. Google Penguin 4.0 not will not put impact on entire site rank, if any single web page is infected with spam activities in search engine. Which is a very interesting knowing for every webmaster.
For details read this: Google Updates Penguin 4.0 (Now Become The Core Algorithm)
MUST SHARE YOUR THINKING ABOUT IT !!