I have decided that it is in everyone's best interests if I disable the ability of members to edit and delete their old messages. However, once you post a message, you have one hour in which you can review what you posted and make corrections as needed. After that time has elapsed, what you have written becomes read only.
Perhaps it vanished after 1 hour past the time you posted the message? That is the time limit or how long after posting you can edit your message as well as the topic line. I felt this was a reasonable amount of time to give, but I can adjust it as you all feel appropriate. Within reason, of course.