Abstract: In a system for tracking activity and delivering advertising over a computer network, the popularity of electronic files is tracked utilizing a plug-in to a system or network, in particular, a file-trading or peer-to peer network. Once the statistical data are obtained, they are stored in a database, and can then be retrieved and compiled and summarized in textual or graphical format. Additionally, incoming file requests to the system are intercepted and demographically appropriate advertising is sent to the requester.