"Compete.com" makes a bold claim. Enter any URL into it's search type interface and it will deliver web site visitation statistics for that site. This is an amazing sales tool if you are looking for a way to compare the web traffic of your site to a competitor's.
But is it accurate?
The numbers that compete.com delivers are not actual visitation statistics, but projections based on a panel of over 2 million web users;
"Based on the daily web usage of more than two million members (and growing!) of the Compete community, Compete calculates and estimates total traffic and rank for nearly every site on the web. We use rigorous statistics to make sure our estimates balance demographic and connection factors that match the entire U.S. Internet population."
Since the sample of tracked users is in the two million range, smaller web sites will likely fall bellow their radar.
Accurate? I say, accurate enough for a sales call and accurate enough to start or deepen a customer dialog.