
Why Alexa graphs disagree with your logs. (Your logs are wrong!) - pg
http://awis.blogspot.com/2007/04/alexa-data-vs-your-raw-logs.html
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lkozma
The only dubious thing is how are people who install Alexa toolbar
representative to the population as a whole. Do they collect some personal
info, so they can correct the bias in the sample?

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joshwa
Yes, if you do shoddy analysis of your logs, your logs are wrong. Spoken like
an Alexa-zon employee. If you know what you're doing, and recognize the
assumptions that go into proper log analysis, logs are a much more reliable
tool than a panel.

The only useful thing a panel gives you is a supposedly fixed standard for
doing competitive analysis... same methodology used across multiple sites. But
even then you have no guarantee that the sample is representative. This is why
companies like Comscore and Hitwise who buy under-the-table clickstream data
from major ISPs (however sketchy and frightening that is) are probably more
reliable than Alexa's panel.

