I have put together a mod for phpBB3 that allows one to bring web forums and mailing lists together. Mostly. There are two parts: the Mail-To-Forum gateway and the Forum-To-Mail gateway. Each forum is configured separately and there is an assumption that each forum equates to a separate mailing list. You could configure one gateway without the other but generally you’ll want both.
The mod can fetch messages for the forum either by polling a drop-path for raw RFC2822 messages or by querying a POP3 mailbox. In both cases the messages are removed after being retrieved.
Messages are parsed in the hope of converting them to basic BBCode. If the author is very careful and tidy when it comes to quoting (contiguous lines prefixed with “>”) then the output isn’t too bad. Signatures are cut off (a blank line followed by two dashes and a space prefix signatures — did you know that?) and line wrapping errors are fixed.
Users are matched based on the e-mail address found in the “From:” header. Optionally new users can be automatically created with a random password or unrecognised senders can be treated as guests.
Outgoing messages are converted from BBCode into reasonably tidy plain-text and sent using SMTP.
The gateway operations need a scheduled task to run periodically. You (the site operator) need to call /cron_mailgateway.php regularly. On Windows it is just a matter of scheduling a task and on Unix you need the “at” and “curl” and other things I don’t know about.
Download it here: Mail Gateway Module 0.0.3