Forrester's Digital Marketing Tracker provides marketers and media professionals with a quarterly update of online advertising revenue trends globally. The tracker captures revenue and user data for 14 key digital media and services companies, which together constitute roughly 90% of the online advertising market. For the first time, in Q3 2020, the tracker also categorizes this revenue into four key channels: traditional search, social, e-commerce, and online banner and video. The downloadable spreadsheet includes quarterly historical data from Q1 2015 to Q3 2020.