Google Personalises Search Results
Google recently announced they are increasing user personalisation. If you are logged in to your Google account then the results returned for your searches will be personalised based on your search history, and possibly your geo location.
In the past Google gave the option to turn off personalised results. This option is no longer present, and when searching you have no way of knowing whether your results have been personalised or not. Unless, of course, you notice that the search results are becoming more and more targeted.
Whilst this may be useful in finding information, it makes it harder to judge how any site is doing for particular searches. If you are looking at where you competitors are positioned, for instance, you will see a misrepresentation of results.
You will see what Google has deemed are the most relevant results for you personally, and not necessarily what your audience is seeing at that point in time.
You can turn off personalised results by clearing your search history and ensuring that you are logged out of your Google account. I would imagine that applies to all Google applications including GMail, Blogger, Analytics, Webmaster Tools and Sitemaps, to name but a few
