Ask Ubuntu is a Q&A site rather than a discussion board, a bug tracker, or a poll/survey site, but I really love Ubuntu and want to discuss those things with other users!
Where can I discuss topics that aren't appropriate to ask on Ask Ubuntu?
(Because this is proposed for our Community FAQ, please add to this answer.)
You can directly participate in Ubuntu user groups and development, and you can find a Local Team close to you if you want to help in your local area. Ubuntu Brainstorm is for proposing and voting on ideas.
Bug reports go on the project's preferred bug report site, or Launchpad. However, if you have a question about behavior you don't understand and aren't sure if it's a bug, or if you are asking for how to work around a bug, that is Q&A and appropriate for Ask Ubuntu.