An Internet forum, or message board, is an online discussion site where people can hold conversations in the form of posted messages. They differ from chat rooms in that messages are often longer than one line of text, and are at least temporarily archived. Also, depending on the access level of a user or the forum set-up, a posted message might need to be approved by a moderator before it becomes publicly visible.

Forums have a specific set of jargon associated with them; example: a single conversation is called a “thread”, or topic.

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.

Depending on the forum’s settings, users can be anonymous or have to register with the forum and then subsequently log in to post messages. On most forums, users do not have to log in to read existing messages.

phpBB

phpBB is an open source forum application. Initially released in 2000, phpBB is currently the most used free forum application with millions of people using the application every day.

phpBB is a high powered, fully scalable, and highly customizable open-source bulletin board package. Whether you want to stay in touch with a small group of friends or are looking to set up a large multi-category board for a corporate website, phpBB has the features you need built-in.

Newer users will appreciate phpBB’s extensive administration panel, which allows the customization of even the most intricate features without having to edit code directly while advanced users will value the ease with which phpBB can be integrated into existing systems.

Features:

• Enables community discussion through an intuitive interface.
• Multiple discussion forums and categories are supported for maximum flexibility.
• Anti-spam tools keep every board free of unwanted users and spam.
• Share files by uploading and attaching them to posts.
• Moderators can help to maintain order by assisting users and enforcing the rules.
• Private messages are direct messages between two or more users.
• An advanced caching system is utilized to increases board performance.
• Straightforward administration settings enable full control over the look, feel, and operation of every board.
• User groups enable users to easily be organized, and then the administrator can fine tune where users can go and which features they can use.
• The powerful search system enables users find topics, posts, and users.
• A powerful plugin system can be used to extend phpBB’s functionality.

FluxBB

FluxBB is an open source forum application. Forked from PunBB in 2008, FluxBB is a popular lightweight forum application, powering forums for Arch Linux and μTorrent.

FluxBB is designed as a lighter, faster alternative to some of the traditional feature heavy forum applications. It is easy to use and has a proven track record of stability and security making it an ideal choice of forum for your website.

Features:

• Easy to use: Simplicity is the key. Featuring a beautiful, clean interface, FluxBB is focused completely on ease-of-use and usability.
• Blazing speed: FluxBB focuses on the most essential features a forum needs and comes without the bloat many other systems bring along, so that you can enjoy the speed.
• Clean admin interface: Take full control over your forum, easily editing permissions, changing board-wide options and rearranging the structure of your forum.
• Flexible permission system: FluxBB comes with a flexible permission system designed to give you full control over your user groups. Allow them to view different sections of your forum, give privileged users moderator status (multiple moderator groups are supported).
• Powerful moderator tools: Administer your board with ease using powerful moderator tools to manage users, banning, censoring, reported posts, forums and topics. Do it yourself or delegate these tasks to moderators as you see fit.

MyBB

MyBB is an open source forum application. MyBB forked from XMB Forum in 2002.

From administration to posting a reply, MyBB is a forum package full of useful and to-the-point features for both you and your visitors, helping you to make running your bulletin board as easy as possible.

Features:

• Rad Community: MyBB’s friendly community will help you get your community started.
• Extendable: Hundreds of plugins and themes make adding new features or a new look easy.
• Simple to Use: MyBB offers an extensive range of features in an intuitive interface.
• Multilingual: Community-maintained translations are available for more than 30 languages.

Simple Machines Forum

Simple Machines Forum is a free forum application. Simple Machines Forum forked from YaBBSE in 2003.

Simple Machines Forum (SMF) is a next-generation community software package that is jam-packed with features, while at the same time having a minimal impact on resources.

Features:

• Advanced permission and user management.
• Tracking of new and old unread topics, not just from your last visit.
• Package manager that automatically installs or uninstalls mods (also known as hacks.)
• Major actions are time and IP locked, preventing ‘hammering’.
• Create child boards under other boards. (sub boards)
• Configure permissions for each membergroup on the board level.
• Both cookie and session based authentication (works without cookies.)
• Ability to choose sendmail or SMTP (with or without authentication.)
• Assign several membergroups to a single member, with one membergroup as the primary group.
• Support of wildcards for email address, IP address, and hostname.
• Include an expiration time for bans.
• Export forum data using XML/RSS.
• Support for WAP, WAP2 and I-mode protocols.
• Members can choose which smiley set they wish to use (or none.)
• Spell Check, Quick Reply, WYSIWYG, ‘Insert Quote’, and other editing features.
• Polls can be added or removed to existing topics.
• Attachment filenames can be encrypted to increase the security (so you can upload .php files, etc.)
• Ability to allow members to use moderation on just topics they posted.
• Ability to Merge/Split topics.
• Recycle bin/board for all deleted topics and posts.
• Options to hide other members’ avatars and signatures.
• Advanced user resources, including the ability to show new replies to your posts.

Vanilla Forums

Vanilla Forums is an open source forum application and discussion framework. Vanilla Forums was initially released in 2006 and today powers discussion on over 500,000 sites.

Vanilla Forums is an open-source, pluggable, themable, multi-lingual community-building solution. It is specially made to help small communities grow larger through SEO mojo, totally customizable social tools, and great user experience. Vanilla is also built with integration at the forefront, so it can seamlessly integrate with your existing website, blog, or custom-built application.

XMB Forum

XMB Forum is an open source forum application. XMB Forum was initally released in 2001.

XMB Forum allows you to build, manage, and promote your online community.