Surely there has to be a math error here right?
Facebook gets an average of 13 pageviews per-user per-day.
Each user visits Facebook an average of 40 times per-month.
This would mean:
a minimum of approx 440 billion pageviews (!) in Dec-2011 
a maximum CPM of 60 cents per thousand page views 
Or = 36 cents per-active user, per-month????????