Abstract: A system for tracking how often content items are accessed by devices across multiple platforms is described. The content items may comprise advertisements. When a device accesses a content item, the device may detect the presence of a tag included with the content item. Based on the tag, the device may send a message to a computing device indicating that the content item was accessed. The computing device may accumulate the received messages and generate a report indicating the amount of exposure of various content items across various platforms and demographics.