django-tidings is a framework for sending email notifications to users who have registered interest in certain events, such as the modification of some model object. Used by support.mozilla.org and developer.mozilla.org, it is optimized for large-scale installations. Its features include...

• Asynchronous operation using the celery task queue
• De-duplication of notifications
• Association of subscriptions with either registered Django users or anonymous email addresses
• Optional confirmation of anonymous subscriptions
• Hook points for customizing any page drawn and any email sent

Please see the full documentation at django-tidings.readthedocs.io.