Compete has a diverse sample of 2,000,000 U.S. Internet users (that come from national U.S. ISPs, Panels, etc) that have given us permission to analyze the web pages they visit and ask them questions via surveys.

Unlike Alexa, we go through a rigorous panel selection and normalization process that involves an independent RDD survey, demographic scaling and extensive QA from our data operations team. Alexa, on the other hand, has a single source of data — its toolbar — so it’s very susceptible to bias.

Check out this interview with Guy Kawasaki about Compete - http://blog.guykawasaki.com/2007/10/ten-questions-2.html