Apologies for the delay in replying Brian, I missed this question
While typing into the message box / editor , your text get's saved periodically. This applies to new threads, posts and conversations, but not profile posts and message editing. You can have multiple drafts at the same time.
This way, you can close the window (or when your browser crashes), come back later and just continue typing where you left off.
You can also click the button that looks like a floppy disc and using the drop-down select to save or delete the draft...
The draft will only reappear in the same forum (when creating a new post) or when viewing and replying to another post.
If you've made a post but can't remember where or if you actually posted it, click the drop-down to the right of Forums tab and you will see the following...
Selecting one or the other of those highlighted options will open up a window showing you your content