Why shouldn't Little Pork Chop make it easy to put a #hashtag at the end of every tweet? Or asked another way, suppose you wanted to put a tag on every tweet. Without it being handled by the software, I don't think there's a non-tedious way to do it.
So now there's new Tag settings panel, where you can enter a tag that appears at the end of every tweet. You can leave off the # if you like, we'll add it for you. If you don't want a tag, leave it empty (the default value).
Not much more to say. A pretty simple feature!