Does the Google toolbar returns different search results ?

I have noticed something very interesting today. Google returns different search results on a browser with their toolbar than it does without the toolbar. I have checked the data centre address returning the results and they are the same on both browsers. I knew that Yahoo was going to add this after reading their new search algorithm patent but Google doing this is a new one on me. We have even tried doing testing via different servers in Europe and still the same outcome, Google returns results differently if you use the Google toolbar.

This brings up some interesting questions: