As I reported last night at Search Engine Land, Penguin 2.0 / 4 is now live - this is the next generation Penguin update. As Google's Matt Cutts added, this impacts 2.3% of English queries and also impacts other languages but the percentage depends on the level of spam in those languages.
Matt officially announced it while on This Week In Google see towards the very end of episode 199.
Matt said on his blog:
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. The change has also finished rolling out for other languages world-wide. The scope of Penguin varies by language, e.g. languages with more webspam will see more impact.This is the fourth Penguin-related launch Google has done, but because this is an updated algorithm (not just a data refresh), we’ve been referring to this change as Penguin 2.0 internally.
As you know, we've been expecting this for some time, since its been over 6 months since the previous Penguin data refresh. Again, this is not just a refresh, but an algorithmic update.
Here are the previous updates:
There are lots of people complaining about ranking declines and some about boosts. It is too early to tell and I do expect to post a poll next week asking you if you were impacted or not.
I deeply hope you only were positively impacted by this update.
Forum discussion at Google+, Cre8asite Forums, WebmasterWorld, DigitalPoint Forums, Black Hat World and Google Webmaster Help.
Update: Matt Cutts tweeted that you can submit feedback to Google via this form about spammy sites this update missed.