Nothing else should be needed. Do they have immediate notifications on all posts? Maybe they are filtered out by tags or other settings? The thing is that there are test cases for emails and they all pass, so it should just work. I would suggest in your case - debug with pdb. Is the send_mail function called successfully?
Evgeny ( 2012-05-08 16:19:51 -0500 )editOne more thing that can go wrong - celery setup. Instant emails are sent via celery jobs - to allow asynchronous email sending. By default celery is disabled by CELERY_ALWAYS_EAGER=True and use of the local database as job queue storage. With the default settings instant email should be sent.
Secondly - set up "instant" email in all categories in your subscriptions - at least just for the test.
Evgeny ( 2012-05-08 16:53:14 -0500 )edit