From what I can make out, the outbox act like two boxes in your emails. I holds your messages while they are being sent, but it also has the same purpose as a draft box. It is worth checking from time to time that things have left it. It happens that messages delayed by the site being very busy are eventually sent. If they are sent they should disappear from your outbox.
Michele, warrior4MS, mother and champion for Ella, the MSer. The solution is out there we just have to ask the right questions.