Google new update penguin algorithm issued 24 April, 2012 to remove the spammy websites and black hat technique from his record. Lots of website are effected some gain the pagerank and some gone done. Our SEO team surprised after seeing the result all website will effected lots. We have checked lots of website are not in 1st which they have no keywords and good Alexa rank, even CSS not validated etc. But still they are on the 1st page and our some website dropped to 2nd page. Google not disclosed what they have changed clearly.
As per internet search we found the below points.
Paid links which are same as keywords of website link are recorded and website pagerank reduced.
SEO persons using comments section to put the keywords and website link to get more and more back link.
Don't be panic you are not the single person whose website is down or up soon it will get the reason.
Give more importance to social media because references about links are more important then search in Google etc.
Use twitter and Facebook accounts and update the customer about services so that customer interest is always remain same.
Remove all unwanted keywords, randomly used keywords from the website page in each section.
Google search title and meta tags automatically and record them with all other internet links which relates to page title.
Be careful about stop search engine in robot.txt and redirect.