The bulk of the changes started at the end of October. Alexa measured the changes Alexa: Has traffic to your site dropped? You’re not alone
As many webmasters and website owners by now know, sometime around October 21st Google changed how they ranked search results. This change, or possibly changes, caused the traffic to some sites to drop by as much as 80%. The Google Webmaster Forums are alive with questions about what happened, and how webmasters should react (for examples see here, here, and here).
Per Webmaster world Many are still seeing their sites changing in position daily
This shuffle happens quite a lot these days…sometimes the shuffle happens more than once per day.
It has also been recently confirmed that google indexes different site differently. All of this points to one conclusion; Sites need to vary methods of where they get traffic from and how they organize their content. A blog is one method, Static content is another, fresh non-blog content is still yet another. mixing content is no longer an option; it is a necessity.
There is nothing new to the SEO strategy of creating different content styles. Most seasoned SEO masters have weather many changes and seen entrance pattern changes in where they get their visitors.
FYI: long tail searchs seem unaffected by Google’s new shuffling and they were unaffected by the instance searches that google started weeks ago as well. They may be receiving more traffic from changes in user search behaviors (not confirmed scientifically, based on a small sampling)