Forums are a focal point of nearly any community or member based website. They are a great place to allow users to interact, tracking topics and allowing information to grow isn't done better on anything else. Much of what people learn and rely on for all types of information from recreation to in depth studies comes from forums. phpBB3 is the most widely used Open Source software on the web and is also incredibly powerful.
The feature set in phpBB3 is immense and there is also a lot of freedom when it comes to styling. This makes for a powerful system that can even be used as a full front facing website if one wanted. Beyond the huge collection of included features, user blogs functionality can also be added with its own set of permissions you can customize. And being an Open Source software means that you get all the source code as well as it being free to use.
Ease of use for a site's users is a very important part of gaining traffic and is becoming increasingly competitive as the market is flooded with easy to use apps and thousands more being released every day. phpBB3 being so familiar to nearly every user and the appealing user interface for entering forum posts, makes it an easy software to implement with positive feedback from your members.
The real power for phpBB3 lies in its user and group permissions settings. Custom groups can be created in addition to the default ones and custom permissions can be assigned to each group. Custom permissions can also be assigned to each user as well. It's easy to create a group and a forum for that group, then restrict access to only that group's memebers. The forum doesn't even display if you're not a member so non-member users don't know they are missing anything.
Login syncing with Joomla can be achieved providing a very powerful front facing public website with an integrated style to the forum for a seemless user experience. Using phpBB3 as the basis or integral part of any community site is an option that should be seriously considered by anyone looking to implement a way for users to easily interact or share information.
phpBB3 can also be used for providing support to customers and clients. Community support is giant part of the internet and anytime several people may have the same question, localizing the conversation and solution is both efficient for the provider and appreciated by the user searching for the answer.
You can read through the huge feature list here:
phpBB3 Feature List
Configuration can be time consuming and styling customizations can take some extra effort at times, but the system is very flexible, reliable, and followed and improved upon regularly. This is a very safe and functional bet to make for forum software that will not let you down as far as features are concerned either.