What do the icons mean that are next to the title of the discussion threads. I see pencils, flames, red xs, locks, bars that look like rating bars and some others. Some I think are obvious, but not always.
The paper & pencil icon is for a regular thread (the replies all have a paper icon - no pencil).
The flame icon is for a "hot" thread - one with 50 replies or more.
A red x indicates the poster self-deleted the post (people can no longer reply in that thread).
A lock shows that the thread has been locked for not fitting the statement of purpose for the forum or group in which it was posted (people can no longer reply in that thread). Posts that have been auto-removed by the software also have a lock icon (when a newer poster is banned, their posts from the previous 12 hours are auto-removed).
The bars icon indicates a thread containing a poll that DUers can respond to - flaming bars indicate a poll thread with 50+ replies.