I can’t tell you the number of conversations I’ve had with fellow web publishers who cite their Alexa ranking with pride. I usually make a bet with them that I can start a site with any random name, and break into the top 10,000 ranks within 1 week. Not that this is a practice I engage in — I’m merely saying this to illustrate my point: that Alexa is severely broken, and will never be an accurate source of web traffic information.
