Threaded discussion is a kind of computer-mediated communication (CMC). Specifically, it is an online dialog or conversation that takes the form of a series of linked messages organized topically. Threaded discussions are text based and asynchronous; they develop over time as participants separated in time and space read and reply to existing messages. Messages in a given thread share a common topic and are linked to each other in the order of their creation. Threaded discussions are particularly useful in online venues where multiple discussions develop at the same time. They grow like crystals, with multiple threads expanding simultaneously rather than evolving linearly. Without them, discussion participants would confront a chaotic, unsorted list of messages on many different topics. By linking responses to messages within a common subject line, threaded discussion makes it easier for participants to focus on one conversation and avoid the distractions of unrelated postings.