Penguin Update 4 (Aka Penguin 2.0) is in action now..

The fourth release of Google’s spam-fighting “Penguin Update” is now live. "We started rolling out the next generation of the Penguin webspam algorithm this afternoon (May 22, 2013), and the rollout is now complete. About 2.3% of English-US queries are affected to the degree that a regular user might notice" stated in Matt cutts - head of Google’s Webspam team in his blog.
But Penguin 4 has a twist. It contains Penguin 2.0 technology under-the-hood, which Google says is equipped withmuch better technology that should stop spam better .

Matt Cutts, Google’s head of search spam, announced during This Week in Google, Episode #199, the new Penguin 2.0 update. Matt referenced the video of him talking about the next generation Penguin update.
Webmasters and SEOs, expect major changes to the search results. Matt specifically said, 2.3% of english queries will be impacted by this update.

Matt Cutts later posted on his blog some more details about this roll out. Matt explained there was an international roll out as well, saying the “change has also finished rolling out for other languages world-wide.” How much of an impact depends on the “languages with more webspam,” i.e. if the French language had more webspam Google France would see a larger impact.

Previous Penguin Updates:

Penguin 4? Penguin 2.0? We could each release of penguin in sequential order, so it’s easy to know when one happened. The list so far:

• Penguin 1 on April 24, 2012 (impacting ~3.1% of queries)
• Penguin 2 on May 26, 2012 (impacting less than 0.1%)
• Penguin 3 on October 5, 2012 (impacting ~0.3% of queries)
• Penguin 4 on May 22, 2013 (impacting 2.3% of queries)
  

But after the first release, the second and third still used the same basic Penguin algorithm with only minor changes. This fourth release is a major change, so big that Google has referred to it as Penguin 2.0 internally.