This post was is large part prompted by Alexa making a change that made the Mattters chart dip a bit - but I’ve been meaning to write this for a long time - as sort of a personal (public) cheat sheet. The change Alexa made, BTW, was to drop Hong Kong (perhaps to fold it into China?) from their international rankings from which they calculate the global Alexa Ranking. Hong Kong was Mattters’ 2nd most popular country (the US is 1st).
We’ll start with Alexa. As you all know, it is based on totaling up the number visitors to website having the Alexa toolbar, i.e. SEO and SEO-savvy visitors, and from these visits extrapolates the total number of visits to a particular website.
The Alexa rank is a comparative rank - which means that since everybody lost Hong Kong, the rank should on average remain unchanged. Except in reality those that had the most traffic from Hong Kong suffered, and those that had the least must of got a little spike in their charts.
This might make more sense if you consider a case, for example, where your traffic may go down quite a bit on weekends. If, on average, everybody else’s traffic went down MORE, your Alexa Rank will then actually go up on weekends.
Quantcast is said to be an completely accurate measure of visits - at least I have never been able to find anyone who questions this (and I have LOOKED!). But in reality it favors… well what it does is it discounts visits from Google [perhaps to the point where it just out and out ignores them]. It does like visits from Yahoo quite a bit - so it is not discriminating against all search engines, just Google. At least this is what I have observed experientially, comparing it against all other sources of data at our disposal. [Also, not sure about Bing (more on bizarro search engine behavior in a different post) or other - from our perspective at this point - minor player search engines].
Compete has one of the lowest numbers for number of visits of any reporting tool we use - but it APPEARS to be largely consistent in its under-counting - can’t really tell though except by comparing it to what other reporting tools say about relative rankings of websites. Funny thing about Compete - the free reporting tools they offer, I mean - is that they update the numbers only once each month and around the middle of the month - so around the 15th I imagine everyone [us anyway!] starts going over there to see if the new numbers are in. This month they didn’t get updated until the 25th or so. Ugh.
Oh, the link to the Compete reports is (took awhile to find this - back in the day):