The content of Internet communication, however, is more complex to describe, but it can often be captured for study. Internet content can be encoded and decoded using a variety of media types (text, graphics, sound, video, executable file). Because of its mediated form, Internet communication often leaves a visible trail of artifacts that can be collected for study. For example, Usenet discussion groups produce a set of articles that can be examined and analyzed. Real-time discourse among a group of participants, such as in MU* systems, can be recorded in the form of a transcript. Other Internet communication artifacts include Web pages, files on Gopher sites, and transcripts of Listserv discussion lists.