The barebones definition of a forum is the ability for people to start threads and reply to other people's threads. However, most forum software provides considerably more than this. Most forum software allows more than one forum to be created. These forums are containers for threads started by the community. Depending on the permissions of community members as defined by the board's administrator, they can post replies to existing threads and start new threads as they wish. A forum administrator typically has the ability to edit, delete, move or otherwise modify any thread on the forum. These moderator privileges are often able to be delegated to other forum members. The reasons for having these abilities are often to allow peace to be maintained and the rules to be enforced.
Forum 4.4.3
With the release of version 4.4.3 of the Forum module comes a new era of stability. The module team has spent several months being rewritting the module and then three months testing the module with the help of a beta team. Critical errors exposed previously have been corrected along with emphasis on multi-portal usage to ensure maximum compatibility in all environments.
Also with the release of 4.4.3, email notifications and permissions have been overhauled to offer the dependability necessary for any high volume community. Email notifications can now be sent via a scheduled task which runs as a background process. This enables high volume communities, such as DotNetNuke, to send thousands of emails to users actively subscribed to discussions without slowing down the performance for the end users. The introduction of the permissions grid, which has been applied at the forum level, which offers administrators the flexibility to set which roles can (or cannot) start new threads, reply to threads, pin threads, lock threads, moderate threads, add attachments, or simply view a forum's content.
While stability and scalability were the predominate focus of the 4.4.3 development cycle, several highly anticipated enhancements have finally been completed and are ready for module users to take full advantage of them. Search was reformed and now users can set Thread status to allow for quick viewing of threads on a particular topic that are either marked Resolved, Un-resolved, or Informative. Notifications forums, link type forums, a new avatar management interface, as well as the ability to prohibit HTML post, disable signatures, and automaticaly trust user capabilities have also been added in this release.
Private messaging is now a built in capability, although not required, of the module. Registered site users can privately communicate with one another without the exchange of email addresses. If this were not enough, users can now locate other site users using the modules built in member list. The member list allows users to search for other site users who have chosen to be listed in the directory. Once found, users can view the member's forum profile, or send them a private message.
One final noteworthy item is the forum themes have been completely overhauled to allow designers more freedom when determining the look and feel of their forum. With the 4.4.3 release, a new theme including all new icons has been bundled with the download. While themes are not as flexible as the built in DotNetNuke skinning engine, they are much more cross browser compatabile than before. (Sample Below, theme actually distributed differs from the example shown below)

All the things described above help make Forum 4.4.3 one of the most flexible forum modules available for DotNetNuke!