Google Panda Minor Update on 19 Nov 2011
Google has been frequently updating to panda algorithm these days. This is a quick update and affects less than 1% search results. This update has been made on 18-19 Nov 2011. Though this is a minor update but may affect some websites. So you need to login to your analytics account and check if it has affected you either in positive or negative way.
Here is the official tweet from Google for the panda update. As stated by Google: this update is to make sure that search result shows the best and high quality content.
So if you are suffering from panda update you need to work on your content and focus on quality of the content.
You can also read Factors that will determine your success with Google Panda to know how you can get success with Google Panda.