I'm interested in watching web sites popularity and there are these web sites like graphbuzz, alexa, compete, quantcast, etc., that give statistics about that. I'm wondering how reliable these statistics are, are they made based on some user feedback or there are some technically real thing that makes possible monitoring site traffic. I will greatly appreciate your input.
So far the info must be taken with a bag of salt . To my knowledge the info is of a unknown % of accuracy . The lack of a global ISP alliance makes it impossible to have accurate information about the global visitor status . ATM i don't rely on any website that claims that they have a valid statistic of the global Internet traffic . The only organization that might implement such a measure is IANA and they lack both the purpose and the technology .