Drupal mail modules notes
OG och mail lists mailman
Webmail Plus is a full-featured email client for Drupal. It's designed to provide email for any or all members of a Drupal site. It relies on a standard IMAP (Dovecot, Courier-IMAP) server for mail storage and localhost or SMTP (Postfix, Exim) server for mail delivery. It's a great way to add email/webmail functionality to your Drupal community site.
Ability to convert emails into Drupal nodes, publishing of email attachments via integration with the File Framework
The Basic webmail module allows one to read and write e-mail through an IMAP mail server. There are not a lot of fancy features (thus the name), just a usable webmail client.
The Comment Mail module allows an email to be sent to the site administrator(s) when new comments are posted. A link in the email allows quick approval, editing, deletion, and/or banning of the poster's IP address.