As many have asked... and that post is Alexa.com in its own ranking?
Amazon ® not published, however sells advertising for this site directly and through Adwords ®, the fact that snooping by DoubleClick Ad Planner, could we have some sites that do not publish their statistics are perfectly visible through the Google search engine.
With these data of October 2010, we know that Alexa.com has no less than 28 million unique worldwide visitors and with 5.5 million come from us.
If Alexa measured if it would perhaps be between 150 to 200 posts in the same ranking.
Finally, with Double Click Ad Planner we can measure any Web site, less to Google....