As someone else mentioned, they use Facebook's own advertising tool to estimate the numbers. And their could be many things wrong with it. But if you put that n

As someone else mentioned, they use Facebook's own advertising tool to estimate the numbers. And their could be many things wrong with it. But if you put that number in the context of other metrics, such as Google trends (http://www.google.com/trends?q=facebook&ctab=0&geo=us&date=all&sort=0 http://www.google.com/trends?q=facebook&ctab=0&geo=u...), then the numbers make sense. Now the question is, are they gonna have slow sustained growth from now on like Skype (http://www.google.com/trends?q=skype&ctab=0&geo=us&geor=all&date=all&sort=0 http://www.google.com/trends?q=skype&ctab=0&geo=us&#...) or fall off a cliff like MySpace (http://www.google.com/trends?q=myspace&ctab=0&geo=us&geor=all&date=all&sort=0 http://www.google.com/trends?q=myspace&ctab=0&geo=us...)? Remains to be seen.