Discourse
Discourse is a forum software that is built for the next decade of the Internet. It features support for threading, categorization and tagging of discussions, configurable access control, live updates, expanding link previews, infinite scrolling, and real-time notifications.
Discourse is used by a wide range of communities. It has many pros such as being a reliable, easy-to-use, highly customizable experience for members. It is also a super-easy way for members to have online discussions.