This will add the text Original Poster to the person who started the thread. It will be added to every post that person makes in the thread except the first post. There are eight locations to choose from to display the text.
If a user clicks on the Original Poster text, they will be taken to the first post in the thread.
It's just a nifty little thing, so in long threads, everyone will know if it is the person who made thread replying in it.