Penguin 2.1 released by Google; affecting ~1% of searches

Google has just released Penguin 2.1--an update to the search engine's spam fighting algorithm. This is the fifth confirmed release of Google’s “Penguin.” The release is a slightly improved version of Google’s “Penguin 2″ second-generation technology.

Penguin periodically looks for sites that are deemed to be spammy but still ranking well, and punishing them. If a website is hit by Penguin, they will see a significant drop in traffic and SEO ranking. Websites can recover from the rank drop by disavowing bad links or manually requesting those bad links to be removed.

Release calendar for Google Penguin

• Penguin 1  April 24, 2012 (affecting around 3.1% of queries)
• Penguin 2  May 26, 2012 (affecting less than 0.1%)
• Penguin 3  October 5, 2012 (affecting around 0.3% of queries)
• Penguin 4 - Penguin 2.0 -  May 22, 2013 (affecting 2.3% of queries)
• Penguin 5 - Penguin 2.1 -  Oct. 4, 2013 (affecting around 1% of queries)