When you've logged in and go to the Forum page, any category that has a new posting will have a flame icon next to the title indicating a new post has been made in one of its sub-forums. Clicking on the category will open the page showing the sub-forums and any one of those that has the flame will have a post you haven't read yet (even if you posted it). EXCEPT the pinned sub-forums such as the Launch Status. If you see the flame at the top level but not once you are in, check the pinned items at the top of the list for new posts they may have.
