It is true that Alexa traffic measuring tool is extremely unreliable since only a small percentage of people have the toolbar installed and that percentage is usually quite biased toward specific services.
However, I thought that one couldn't simply press F5 using browser with Alexa to get a high ranking.
Pretty sure they count one IP as one hit, or I could be wrong.
You'd have to go out of your way to use a proxy or something similar to pump up your own score.