Mark Jackson posted an article at Search Engine Watch about the impact of Google’s evolving Personalization including it’s affect on rankings.
He mentions a statement that Bruce Clay shared in a Pubcon 2008 session, “2009 will be the year of the end of the ranking report.”
We’ve been trying to wean clients (and ourselves) from the addiction to ranking reports focusing instead on the much more important metrics of actual traffic to the site, conversions, and ROI.
As Mark says, “In the very near future, you will no longer be able to reliably check your rankings in the Google search engine”… [More and more] Google is personalizing the search results based on your recent search engine queries. They say specifically that based on your location and/or your recent search activity the search results have been altered.”