Persistent conversation is human-to-human interaction carried out over computer networks; it is produced by typing, speaking, or other means. Unlike face-to-face conversation, however, it leaves a trace-in the form of text on a computer screen, sound files, etc. that persists for varying amounts of time. Examples of persistent conversation include interactions carried out via group chat, IM, texting, MUDs, email, newsgroups, web boards, blogs, wikis, 3-D virtual environments, and other digital media.