The document summarizes key insights from Opera Mediaworks' Q4 2012 State of Mobile Advertising report. It finds that Q4 was a record quarter for mobile advertising requests and revenue. While iOS generates the highest revenue, Android surpassed it as the leading mobile phone OS for impression volume. Music, video and media publisher sites generated the most impressions, while arts and entertainment saw the most revenue. The report also notes the rapid growth of mobile advertising in international markets like Russia. Finally, it provides examples of innovative mobile ad units that leverage new device capabilities.