Exposure to media content across multiple media delivery mechanisms is measured, so as to generate reports of aggregate exposure over multiple delivery mechanisms. The delivery mechanisms can include, for example, television and radio, as well as Internet delivery of web pages or other content viewed on a computer, mobile device, or other electronic device using a browser or other application. Reference signatures are generated for media content items of interest. Monitoring devices and/or software monitor user exposure to media items across multiple delivery mechanisms. Intercepted signatures are generated for the monitored media items. Reports are generated based on comparison of the intercepted signatures with the reference signatures, including analysis of media exposure across multiple delivery mechanisms.