Constant Content

How do you know if a request has been fulfilled or not? There are a lot of requests but some are rather old and I am assuming have already been fulfilled

In my experience, the old requests are usually no longer needed. It is up to the customer to remove the request, and they don't always do it. With the Q and A button under the request you can jot the requester a note and ask whether or not they need more articles. If you don't hear from them, it's a safe bet they don't.