A discussion group on the Web about a particular topic. It is similar to a Usenet discussion (see newsgroup), but uses the Web browser for access. Before the Web, text-only forums were common on bulletin boards and proprietary online services (see BBS). Web-based forums can include all the extras people expect from Web pages, including images, videos and downloads.

Although they can be entirely anonymous, forums often require registration of an e-mail address, username and password. Messages may be displayed in chronological order of posting or in question-answer order (a user posts a question, and all related answers are displayed under the question). See message thread.

Turn a Site into a Forum
There is a variety of forum creation software for the Web, typically written in Java, PHP, Perl or ASP. The software can be used to create forum-only sites or to add a discussion section to any Web page. See discussion group.