Have you ever started writing a post, then gone to check something somewhere else on the forum, only to lose your partially-written post?
You can fix that.
Just edit your profile, and look for this item under Settings:
Set it to "Yes". (It's set to "No" by default.)
Then be sure to click on "Save account settings".
Now you can come back to the thread you were writing on and when you do, you'll see something like this:
Just click "yes" and you're back in your original message. Also, if you are writing a post and forget to actually post it, this feature will warn you before you try and create another post. Neat-o, huh?