This makes sense of traffic losses webmasters were seeing that didn’t exactly jive with the purpose of the EMD update, in cases where domains were branded or otherwise not geared toward matching queries.
Matt Cutts told Search Engine Land, “Google began rolling out a new update of Panda on Thursday, 9/27. This is actually a Panda algorithm update, not just a data update. A lot of the most-visible differences went live Thursday 9/27, but the full rollout is baking into our index and that process will continue for another 3-4 days or so. This update affects about 2.4% of English queries to a degree that a regular user might notice, with a smaller impact in other languages (0.5% in French and Spanish, for example).”
The last Panda shakeup came in mid-September, by way of a data refresh. This latest update is an actual change to the algorithm.
Panda has been the cause of much confusion and angst in the webmaster world, where Google’s guidelines on content quality leave much to be desired. To that end, Google updated their Webmaster Guidelines earlier this week and we’ve put together a 23-point web content quality pre-publication litmus test to help publishers out.