Here is a good example of how "inaccurate" (U.S.-biased) Alexa, Compete, and Quantcast are. Xing is a popular social networking service much like LinkedIn. LinkedIn is very popular in the U.S., while Xing is very popular outside the U.S., mainly in Europe. They recently announced they have 2 million users, just like Simpy (heh). You'd imagine some pretty impressive numbers and charts from Alexa, Compete, and Quantcast, right? Unfortunately, no. All three services are so biased towards the U.S.-only visitors, that Xing's numbers look pretty bad: Alexa, Compete, Quantcast. Ouch!
Xing is clearly not alone. A good portion of Simpy's users are non-American. This is not surprising - Simpy has been translated to a number of languages. If you look at simpy-user or simpy-dev lists, you will notice people from (Western) European dominate in numbers/activity.
Sure, the services clearly state that the numbers they show reflect only U.S. visitors, but what good is that? That's like reporting the population of the planet Earth at about 300 million and saying "but this represents only the U.S.". Give us the rest!
