Couldn't resist the title - sorry. I mentioned in a tweet earlier today that if you want to turn off the Google personalisation you can add "&pws=0" (the "pws" stands for "personalized web search") to the end of the Google search url to turn it off.
Here's another tip, if you regularly travel from country to country and get fed up with Google redirecting you to a local variation, which may well not be in a language that you understand. Use: http://www.google.com/ncr to disable this function, with NCR=no country redirect.
Worried about personalization? Did you know that Google personalizes your results? If you're logged into your account Google takes into account your web search history, and also your location, IP address and cookies. Those last are important, because even if you don't have a Google account, what you see is not necessarily what someone else will see. We've gone beyond the days of search results being the same for everyone. You probably won't notice the personalization element, because if it's well done, you'll just see that you get good results - or what are good results for you. You can easily check this by taking a look at a set of Google results. At the very bottom of the page (or perhaps to the right of the search box) you may see an option to View customizations and this will tell you if your results have been personalized or not. You can also see what the results would look like without it. There's more on customizations in an FAQ response and more details on localization as well.
Is this something that should concern you? I think that it probably is. Firstly, it's not clearly stated that Google is doing this. Yes, I know there's a bunch of pages which I've linked to that explain this. And yes, there's the view customizations option as well. If you knew about that, all well and good, but in my view, the link to customization is so far down the page, how many people are going to see it? Secondly, if you're working with a client/user/etc you need to be aware that saying 'do a search for xxx and it's the third result down' doesn't actually work too well - it cannot be relied upon. I suspect this is something that causes much confusion, certainly within the search optimization world. If your machines are public access, it's worth remembering that they'll return certain sets of results based on the set of users that you have. This is great when you're working with those users, but if you happen to use a machine for a totally different type of search, the personalized results won't be much help. And you may not even realise it.
Here's another point, and it's one that I don't want to push too far, but it's worth making. If Google localizes results based on a particular country, and people have a certain belief system, with the majority of people clicking on a certain type of result, might this not then emphasis the majority view of something? So, if a country has a specific religious system that decries homosexuality, could not Google results end up returning results that would be inclined to rank homophobic results higher than they would normally be expected to? I'm not saying that this is the case - I doubt that it is but couldn't say for sure - but the point is that it could be. Even if it isn't now, it wouldn't be hard to do. Can you trust a search engine with your results? Is a search engine as unbiased as an information professional? It's not difficult to 'googlebomb' the engine to get results that really shouldn't be happening (the famous 'miserable failure' for G. Bush's biography is an example), and while Google says that they've ensured this can't happen by tweaking results, it's still a worry. What you end up with is confirmation bias. This isn't helpful. I'm not going to say that you don't also get it with an information professional, but I'd be happy to bet that it's a lot less than you'll find with a set of computer based algorythms.