Why does my site rank differently in Google when I search on different computers?

When I search for the keywords that I am targeting with my site, on my computer, my page ranks on the first page (second in the list), but if I go onto my wife’s computer, same internet connection, same room and do the same search, my site is way down the list on the 2nd or 3rd page.

Is there a way of determining how effective my SEO strategies are other than doing a search for those terms in google?

[font=calibri]Google knows who you are! If you are logged into your Google account, then it’s dead easy. If you’re using the same browser on the same computer then it could still be keeping track of you.

And what Google is trying to do is to give you the results that it thinks are most relevant to you. That means that sites you visit a lot will get moved up the results list, because Google knows that you like those sites. What you’re seeing on your wife’s computer is much more likely to be a fair reflection of what everyone else is seeing.

The easiest way to keep tabs on it is to have a browser (or ideally a computer) that you never look at your website on. Then you can do as many searches as you like, and as long as you don’t ever click through, Google will not be able to associate you with that particular website, so it won’t move it up the rankings for you.[/font]