I would like to see functionality that would allow people to create mailing lists that could then be used to send e-mails to subscribers of the list.
The actual e-mail address of the subscribers would remain anonymous.
Only logged in users could send an e-mail using a group.
There should be a way to complain about particular users who abuse the list by sending spam e-mails.
There should be a way to enable or disable particular users from using a particular list.
The system should keep statistics and counts about the sending of e-mails using the list for each user so that people who are using the service excessively can be identified.