Also known as a message board. An online site dedicated to discussing a particular topic. Unlike a chat room where the conversation is built upon short, rapid-fire responses, discussions in a forum are published through a thread often longer than a single-line of text. Conversations are typically archived. In some circumstances, moderators approve each post before they become visible.

A discussion forum is hierarchical or tree-like in structure: a forum can contain a number of subforums, each of which may have several topics. Within a forum’s topic, each new discussion started is called a thread and can be replied to by as many people as so wish.