This document summarizes the findings of the IAB Adex Benchmark 2012 study on the European online advertising market. It found that the total value of the European online ad market in 2012 was €24.3 billion, an 11.5% increase from 2011. Search advertising continued to be the largest format with 48.8% of total online ad revenues, though display and classifieds/directories also saw strong growth. Mobile revenues remain a small percentage of total online but are growing significantly. The outlook suggests continued growth in online advertising driven by expanding access to fixed and mobile internet across devices.