So, this is probably a dumb question.
I saw a TED talks speaker demonstrate how Google and Facebook personalize their results. For example, Facebook news feed tends to show only the people you read regularly. Google checks which IP you're coming from, where you're located, what you've searched recently, what other people in the area have searched, probably the bounce rate of the pages they went to, etc etc in order to make your own search result page. So when you say, "this site ranks in the top 3 for keywords x y z" how do you know that's the real rank? Maybe their algorithm saw that you keep looking at the target site so they moved it up?
I saw a TED talks speaker demonstrate how Google and Facebook personalize their results. For example, Facebook news feed tends to show only the people you read regularly. Google checks which IP you're coming from, where you're located, what you've searched recently, what other people in the area have searched, probably the bounce rate of the pages they went to, etc etc in order to make your own search result page. So when you say, "this site ranks in the top 3 for keywords x y z" how do you know that's the real rank? Maybe their algorithm saw that you keep looking at the target site so they moved it up?