Monday, June 18, 2007
If you have Web History turned on in your Google account, it might.
Google learns from your past searches and what you click on to custom-tailor future search results. This might not be a problem most of the time, but if you're trying to see how well different sites rank, then you'll be getting biased results.
It might also be the case that personalized Google results are actually worse than regular results.
To get "clean" Google search results, you can append "&pws=0" to the end of the Google search URL or install a Google Search plugin that does it automatically for you. Luckily, this plugin works on both IE7 and Firefox.