In areas such as Japan, registration is frequently optional and anonymity is sometimes even encouraged.[29] On these forums, a tripcode system may be used to allow verification of an identity without the need for formal registration. People who do not register and/or post are often referred to as "lurkers".

Comparison with other web applications

Electronic mailing lists: The main difference between forums and electronic mailing lists is that mailing lists automatically deliver new messages to the subscriber, while forums require the reader to visit the website and check for new posts. Because members may miss replies in threads they are interested in, many modern forums offer an "e-mail notification" feature, whereby members can choose to be notified of new posts in a thread, and web feeds that allow members to see a summary of the new posts using aggregate software.There are also software products that combine forum and mailing list features, i.e. posting and reading via email as well as the browser depending on the member's choice.

Newsreader: The main difference between newsgroups and forums is that additional software, a News client, is required to participate in newsgroups whereas using a forum requires no additional software beyond the web browser.

Shout boxes: Unlike Internet forums, most shout boxes do not require registration, only requiring an email address from the user. Additionally, shout boxes are not heavily moderated, unlike most message boards.

Wiki: Unlike conventional forums, the original wikis allowed all users to edit all content (including each other's messages). This level of content manipulation is reserved for moderators or administrators on most forums. Wikis also allow the creation of other content outside the talk pages. On the other hand, web logs and generic content management systems tend to be locked down to the point where only a few selected users can post blog entries, although many allow other users to comment upon them. It should be noted that the Wiki hosting site known as Wikia has two features in operation, known as the Forum and Message Wall. The forum is used solely for discussion and works through editing, while the message wall works through posted messages more similar to a traditional forum.