This is a comparison of the features of various Internet forum packages.

Subarticles

This article is a broad-brush comparison of some of the major features of the various Internet forum software packages currently available. This page highlights major features that the manager of a forum might want and should expect to be commonly available in different forum software. The subarticles below provide more detailed comparisons of specific software packages within categories defined by the software's architecture (ASP, PHP, etc). For detailed comparisons of forum packages from the different architecture classifications, please see one or more of the links listed below or one of the web sites listed under External Links.

• Comparison of forums written in ASP and ASP.NET
• Comparison of forums written in PHP
• Comparison of forums written in other languages

Note: These comparisons do not include remotely hosted services (such as Proboards or ZetaBoards) which use their own proprietary software, rather than offering a package for download which webmasters can host by themselves.

Feature explanation

Below is a brief explanation for each of the features compared in the subarticles. For a forum to qualify for a feature, the functionality must be available out of the box, not as an add-on, plugin, etc.

Flat vs. threaded

• A flat forum is one where each message is added onto the end of the discussion, with no set relation to any prior messages (other than being on the same discussion topic — except in case of Off-Topic posting). But, there is normally a feature to 'quote' another person's post, to allow reference back to other posts.
• A threaded forum is one where each message must be specified when replying to a previous message, allowing multiple discussion threads to evolve from a single initial discussion item.

Forums can either support one or the other of these methods, or both.

Duplicate thread prevention

Google has introduced a new concept in Google Groups to reduce redundant threads and therefore helping moderation of forums. Basically, the idea comes from the fact that many users do not bother to search a forum and directly create new threads to seek an answer to a question. When the user types a new thread subject it brings up similar threads automatically on the side. This helps keep the number of redundant threads (or the overall forum pollution) to a lower level as users that neglect to search for a topic and are posting a thread may find the answer to their question as they are creating the new thread. In essence it's a search combined with creating a thread. Instead of having to search the forum, and then creating a thread if there is no satisfying answer, this duplicate thread prevention allows the user to go and seek the answer to a topic. In Google Groups this feature likely uses AJAX type interface and only draws from the subject field of the thread to find similar threads.

User-selectable themes

Most forums provide an option for the forum owner to customise the look and feel. Some forums also allow the administrator to create multiple styles or themes, and allow the user to choose which one they wish to view. Themes may simply be a different set of colours and graphics, or they may involve a different layout to the forum, such as one optimised for small-screen devices.

Calendar

Some forums provide calendar functionality for storing events and appointments, either per-user or as a forum-wide shared calendar.

Image attachments

Most forums provide the option for a user to upload an image along with a message posting. This is usually accompanied by a space limit (eg: 1MB per user) to prevent users from filling up the forum host's webspace. Some forums also allow other types of file to be uploaded.

One major usability issue is whether images can be uploaded to a forum and displayed inline in message postings easily (or at all). The presence of "image attachment uploading" does not imply that in-message display of images within the flow of message text is possible (or if possible, easy to achieve).

Unread message tracking

Unread message tracking refers to the way that is used by forum software to track and display messages that have not yet been read by the current user. This can be one of the following:

• Session ? when a user's session starts, this method relies on the user's "last visit time" to display all messages created since that date as unread. Everything that was posted before "last visit time" is considered "read" regardless of whether the user has actually seen it or not. Until the user's session expires, this method properly tracks read/unread messages, starting with messages that were selected as "unread" when the user's session started. This method is broadly used, due to the simplicity and speed benefits of only storing and checking against a single database value.
• Full ? forum software which properly tracks what messages have been read or unread by each user, regardless of user session expiration. Some forum software also allows the user to 'mark as unread', so that they can come back to a message later.

External links

• Admin Zone Forum Software Discussions
• Online Comparison of Forum Software at Forummatrix.org
• Comparison at Foren-Infos.net (German)

fr:Comparaison des logiciels de forum Internet