Web site traffic statistics

This question came to the Communications Librarian's listserv:

I'm looking for credible sources of web site statistics that I can use to verify/estimate the number of visitors to a few specific sites I am studying. I want to quote a source more objective than the website sponsor's own statistics. Is there such a source?

A site called Alexa.com is useful for just these sorts of questions. Click on the "Traffic Rankings" section, type in the address of the site you want to track and you'll find daily, weekly, and monthly rankings, other sites that link to the site, and more. For instance, you can compare two sites. (I compared two competing Communications Schools, interesting...). I notice that for sites that fall beneath the top 100,000 weekly and monthly hits are provided, but not daily.

There are many web counter products out there. The Open Directory Project lists a bunch of them. You may also want to check Nielsen NetRatings for general information about net traffic, (such as the top ten web rankings in different countries), press releases, etc. But they don't offer anything as specific as Alexa to play with for free.

Web counters are not the most reliable statistics for many reasons, one being that counters base their counts on IP addresses and not specific computers so users may be counted multiple times. Like all ratings they are crude, but still manage to mean something, or so enough people think.