London and San Francisco – Facebook's average Cost per Thousand impressions (CPM), an indicator of what Facebook earns per ad served, has increased by a significant 58 percent over the last 12 months, since the second quarter in 2011. This was revealed in the latest Global Facebook Advertising Report compiled by TBG Digital and verified by the University of Cambridge. It is the latest report examining the trends and changes in the performance of Facebook campaigns managed by TBG Digital, … [Read more...] about Facebook is earning more per ad