After Panda, Google has launched another algorithmic update to fight webspam. This algorithmic change, better known as the “Penguin update” was launched on April 24, 2012 and it affects 3% of all search queries.

Panda was launched to address the issue of low quality content. But Penguin has a slightly different goal - to find sites that violate Google’s content quality guidelines and use unfair means to gain higher ranks in Google search results. No wonder, millions of site owners use all sorts of black hat techniques to gain rankings and Penguin has been launched to address all those issues.

Compared to Panda, Penguin is broader in nature. What this means is that even if you have high quality content on your site, if you have used black hat techniques to gain rankings, your site’s traffic will take a huge dip (after the site gets flagged by Penguin’s filter).

In some extreme cases, it will be difficult to recover from Penguin’s hands because once you’ve done a lot of low quality link building, it is impossible to reverse the effect. That’s not the case with Panda, as it is possible to recover from Panda’s grip, provided you remove or improve all the low quality content on your site.

To know whether your site was affected by Google’s Penguin update, check your site analytics program (Google Analytics, Sitemeter, etc). Do you see a big dive in the organic traffic from Google on April 24th, 2012?

If "Yes" is the answer, I am afraid, your site has been hit by Penguin.