A method for tracking abandonment rates. A client computer may send a first message to a server requesting a content unit to be incorporated into a web page. The client computer may receive, from the server computer, the content unit including deliverable content and a communications element configured to send messages generated by the content unit to the server. After delivering the deliverable content, the client computer may send a second message to the server via the communications element, the second message indicating that the delivery of the deliverable content has been completed.