phpBB is used by millions of people on a daily basis, making it the most widely used opensource bulletin board system in the world. 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.
SMF in short is a free, professional grade software package that allows you to set up your own online community within minutes. Its powerful custom made template engine puts you in full control of the lay-out of your message board and with our unique SSI - or Server Side Includes - function you can let your forum and your website interact with each other.
Vanilla Forums are open-source, standards-compliant, customizable discussion forums.
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.
PunBB is a fast and lightweight PHP-powered discussion board. Its primary goals are to be faster, smaller and less graphically intensive as compared to other discussion boards. PunBB has fewer features than many other discussion boards, but is generally faster and outputs smaller, semantically correct XHTML-compliant pages.
bbPress is forum software with a twist from the creators of WordPress. bbPress is plain and simple forum software, plain and simple. It’s easy to use, easy to administrate, fast and clean. But don’t let its simplicity deceive you; underneath the gleam, it’s got some powerful features and is highly customizable
FUDforum (Fast Uncompromising Discussion Forum) is a free and open source web discussion forum. FUDforum combines an extensive feature set while maintaining the ability to generate forum web pages extremely fast. The forum includes i18n and templating support allowing for a complete customization of its output as well as a very capable group based permission system. FUDforum can also act as a Mailing List Manager, USENET newsreader and even an XML Feed Aggregator. This will allow you to build an instant community and consolidate all your messages into a single system.
miniBB is a standalone, open source program for building your own Internet forum. If you want a lite, simple and stable message board attached to your existing website at the very high integration level, which may include the full customization of the layout to the look of your website, or even synchronizing with the existing membership system, you've just came across to the best forum solution for such purpose available worldwide.
Beehive is an online forum/message board system with several powerful features. Beehive is an open-source project for creating a high-configurable frame-based discussion forum. Almost every aspect of Beehive is customisable to some degree, from the forum's name right down to how many posts per page each user wants to see, and with everything inbetween, including guest accounts, user profile catagories, your start page, your top frame, user's signatures, language packs, forum styles and emoticon sets - and if you don't like those that come as standard, it's easy to create add your own!