- You use it just like any other forum/discussion board. People can create topics to which other people can reply to. Moderators (which you choose, if memory serves me well) can pin topics to the top, too, as well as delete topics and replies.
- You should use it if you plan to offer more in-depth support for your project, such as a tool.
- A comment hierarchy is a thread of two or more replies to a topic or comment.
- “sticking” a topic means it will always remain at the top. It “sticks” to the top, instead of being pushed down as new topics are created. You and moderators can make a topic “sticky”.