GoogleAlgorithmConfirmedHigh impact
Panda 2.0 (international rollout)
Panda extended beyond the United States to all English-language queries worldwide, with user blocking data incorporated as a signal.
What changed
The second Panda release applied the quality classifier to English-language searches globally rather than only google.com, and Google said it began incorporating data from users who had blocked sites in search results. Many non-US publishers experienced their first Panda impact at this point. Google's guidance remained unchanged: improve overall site quality rather than target individual pages.
Timing
Rollout began 11 April 2011. No completion date was announced. Rankings typically remain unstable for the whole rollout window, so measurements taken inside it are not a reliable read on the outcome.