FUDforum is a super fast and scalable discussion forum. It is highly customizable and supports unlimited members, forums, posts, topics, polls & attachments. It can import XML Feeds and sync with USENET groups and Mailing Lists (bi-directional).
...The concept is fairly simple:
* You configure your mail server to send a copy of every mail that it processes to a specific mailbox
* You set up autoreplybot to poll this mailbox, either via POP3 or IMAP
* Users log on the autoreplybot web panel using their mailbox credentials (which autoreplybot validates against the mail server) and write their 'out of office' messages in a simple html form.
* When one of your users configure an "out of office" reply, autoreplybot sends this message back to every person that write an email to the user.