Originally Posted by AdultAds

Babsy,

You're correct, but Alexa has it's toolbar on enough machines that it can predict accurately within a 95% confidence interval (stats talk, sorry) that the numbers are correct. It's kind of like the election polling statistics. They don't poll the whole country, just enough to make their results statistically accurate.

In one given day, variations could cause it to over or under-report numbers, but if you look at weekly/monthly averages it should be a representative number.

-AdultAds