MY views ...
1. No, but it would be a great ER to raise. If you haven't seen enhancement already, rummage around on the enhancement request section of this portal.
2. If the service isn't running, the emails just stay in the normal mailbox waiting to be processed.
3. This is for enabling the feature where people send in an email with the right keyword at the front of the title (default update:). The product then composes an email by running a particular crystal report or query and sends the results back in an email to the person who sent the email. It is very briefly descibed on page 130 and 135 of the 732 LDSD Administrator.pdf Personally I find self service better in terms of providing feedback to end users, but this update feature is there for mail users.