<dextel@gmail.com> wrote
> 1) I don't want his emails to be flagged as spam especially since his
> subscribers may be sending a lot of emails and we have no control
> over to whom they're sending it.

Make sure your system is set up to use two-way verification, so the
recipient has to request the mailings and then confirm via an email your
server sends out that they want to receive the mails. That way you are
covered against people who forget they subscribed and you also are sure your
messages are going to the right person.

> 2) I don't want his IP to be blacklisted either and then all
> subscribers won't be able to send emails.

Most RBLs are generated by using spam-traps. That is, addresses which have
enver been published. If your system is sending to legimiate recipients who
requested the messages, then you should be safe. If some other RBL lists
your server due to recipient complaints, you will be able to show them proof
from step 1 that the email was requested.

> 3) I don't want to overload or slow down the server if so many emails
> get sent everyday...

I guess that is more up to you to set some limits on your software.

Brian