Personal Search Results
It has been widely thought in the SEO community that Google could/will if possible serve up a different set of results per person – providing they are signed into a Google account – as a personalised search results. I have seen examples of this happening so it does exist.
That said Google have said that the amount of users who see personalised search results are very small and most people who are using the same language and location will see the same results.
Location and language is much more influential.