Last Monday, Compete.com released the January ’09 numbers for the top 25 social networks.

I decided to have a closer look at those numbers and compare it with the numbers from another audience measurement company: Quantcast

As you can see from the two images below, there is a big difference in the numbers from Quantcast and Compete. Compete.com uses a U.S. based panel for its reach estimates. Quantcast uses an inference-based, direct measurement methodology. Quantcast also offers a direct measurement solution for web site publishers. Continue reading →