Alexa Graph Changes

Still a poor source of data though

[dcheney]

Howdy,

I just notice that the Alexa graphs have significantly changed. They have have a tab for Reach, Rank, and Page Views. Previously only Rank was available (at least in graphical form).

Presumably it still has the same ol' flaws: namely data based on a very limited set of users who have installed the toolbar.

[cgrantski]

Nielsen, Comscore, Hitwise, Alexa etc all use similar approaches, don't they? some kind of panel based on having a monitoring tool installed. I'm sure the representativeness and size of the panel varies from company to company, as does the ability of the company to mathematically extrapolate from sample data to estimates for the full web population.

But I've checked Alexa's estimates against real information and while the absolute numbers are off, the relative numbers (relationships) were pretty decent, certainly better than our guesses. I did the same thing for Comscore etc a couple years ago and saw about the same thing. Haven't checked Hitwise however.

People here seem to think highly of Hitwise's numbers - does anybody know enough about their methodology to explain more?