The present invention relates to methods of, and systems for, tracking content in communication networks by collecting content transmission information from the network. The collected content transmission is examined to identify discrete content items, and these are compared to predetermined content items. The result of the comparison is stored on a database, and if an identified discrete content item is the same as or substantially similar to a predetermined content item and/or if an identified discrete content item has been previously sent to or received by a subscriber or application, an event signal is triggered.