A WebmasterWorld thread asks a question and paranoia (might be an extreme word here) I had myself about turning off personalized results. In short, people in the SEO world, mostly, try to turn off personalized results when searching on their keywords to see how they rank. Personalized results, especially on keywords you manually check often, can make a significant difference in the ranking of those results.
The WebmasterWorld thread asks if turning off personalization really works. Like I said, I often wonder if the &pws=0 feature (adding &pws=0 to the end of the search URL turns off personalized results) still indeed works. There are other ways people use to make sure that their search results are not personalized, such as logging out, using different browsers, using proxies and so on.
But Google can use other means to personalize the results, such as:
1.) Browser Configuration, Including: Plug-In Versions, UA String (which usually includes OS), Bookmarks 2.) Installed Fonts 3.) IP Address 4.) Geo-Targeting 5.) ISP 6.) Routing Information: EG Trace-Route? 7.) Similar Search Patterns 8.) Connection Speed
So do you think &pws=0 fully works? WebmasterWorld.