Images: ReadNotify's tracking service
Screenshot
During congressional hearings, Hewlett-Packard investigator Fred Adler specified how the company bugged the e-mail it sent to CNET News.com reporter Dawn Kawamoto. HP used the services of ReadNotify.com, one of several online companies that let people plant bugs in e-mail messages and files. This is a screenshot of the ReadNotify home page.
Instructions
ReadNotify also offers plug-ins for various e-mail clients, including Web-based e-mail, to make bugging a message easier.
Document generation
Paying users of ReadNotify.com get the ability to add bugs to files, such as Office and PDF documents. This is a screenshot of the ReadNotify Web page that will generate a document with an image. This image, a green check mark, can simply be dragged-and-dropped into the document that needs to be traced. The check mark becomes transparent after it is dropped.
Detailed report
Additionally, if a message is forwarded, the report states the probable e-mail address of the individual it was sent on to. It also displays if a message is reopened by anyone.