Penguin 2.1 launching today. Affects ~1% of searches to a noticeable degree. More info on Penguin: http://t.co/4YSh4sfZQj
— Matt Cutts (@mattcutts) October 4, 2013
Penguin is an update that affects sites that are having a spammy link profile. Remember, Google always looks for natural links and not just relevant links. If you feel your site is affected by this update, then have a look at this Penguin 2.0 recovery guide.
Also See:-
Google Penguin Update
Google Penguin 1.1 released on 26th May 2012
Google releases Penguin Update 3
Low Quality Link Profile Asking for Sure Trouble?
How to Use Google Disavow Tool?
What Exactly is a High Quality Backlink?
Google Working on Providing Samples of Unnatural Backlinks
How to Create Backlinks that Google Loves
Seo Secrets
How to rank in Google
Are You Making Your Website Vulnerable To Future Google Updates
Battle of Ranking Continues
