From the very beginning of the Google Age (which wasn't that long ago) I asked myself if the various national versions of Google would yield up the same results.
And the answer is a resounding NO. If you enter any given search query in, say, google.com or google.it, you will get different results. Far be it from me to explain the differences- no one really knows what Google's algorithm is.
But see for yourself. Enter various search terms related to Italy and you'll see the difference. If you know Italian, using google.it is a good shortcut to get to the more authentic stuff, written in Italian for Italians (per capirci). Select the option "pagine in italiano" or "pagine provenienti da Italia." This is a good way, for example, to get to authentic recipes and insiders' info on tourist locales. In other words, if you enter "Capri" or "risotto" in google.com or google.it you will get results that differ by quantity and quality, and you can bypass countless American sites telling you how to prepare carbonara or visit Venice.