Actually, I'm surprised it's so high (150,637 as of today). It means quite a lot of HN visitors (which are not necessarily just registered HN users) have insta

Actually, I'm surprised it's so high (150,637 as of today). It means quite a lot of HN visitors (which are not necessarily just registered HN users) have installed Alexa toolbar. Which is what ultimately Alexa rank mean. It is a huge source of bias - different types of sites have very different likelihood that their visitors would have installed Alexa toolbar.