oSpam is an anti-spam system based on Perl, qmail, and, optionally, vmailmgr. It features "one-day" email addresses for usenet postings: after a delay, the mails sent to your address will be put in quarantine waiting for a confirmation, or/and can be used as your main email address: all your contacts are listed in a file. If somebody which isn't in the list sends you an email, he will get a small and unique confirmation request, and then the email(s) will be delivered transparently.
