The Penguin Update launched on April 24. It was a change to Google’s search results that was designed to punish pages that have been spamming Google. If you’re not familiar with spam, it’s when people do things that violate Google’s guidelines. To learn more, see these pages:
For context, the initial Panda change affected about 12% of queries to a significant degree; this algorithm affects about 3.1% of queries in English to a degree that a regular user might notice. The Penguin change went live for all languages at the same time.
Does Google consider SEO to be spam?
There have been at least nine major updates to Google’s “Panda” algorithms since they were introduced last February to purge search results of duplicate content. Matt Cutts announced Google is updating its algorithm this week targeted at webspam including keyword stuffing, cloaking, and link schemes from search results.