Google has used Twitter to notify users about its ongoing updates to the Panda algorithm that targets low-quality websites. Google estimates about 1.6% of queries are affected by this update. At present, SEO commentators are unsure of the exact details of this update due to the brevity of the announcement.

What is the Panda update?
In February 2011, Google launched the Panda update designed to filter low quality content from its search results, thus causing publishers to think very carefully about producing higher quality content. It is a filter that runs periodically, therefore each time it runs all the content that Google is aware of is resifted and poor content is caught out. This update was brought about through complaints that poor content produced by ‘content farms’ were making search results less relevant.
For more details on the previous Google Panda updates, check out this infographic from Search Engine Land.