OpenBlock users can subscribe to email alerts from any location they're interested in.
In order to support this feature, there is a script that needs to be called regularly. You can do this any way you like; cron would work fine.
Here's an example crontab file that sends the daily alerts once a day, and the weekly alerts once a week. Adjust the environment variables as needed:
DJANGO_SETTINGS_MODULE=obdemo.settings VIRTUAL_ENV=/path/to/my/environment @daily $VIRTUAL_ENV/bin/send_alerts --frequency daily @weekly $VIRTUAL_ENV/bin/send_alerts --frequency weekly
Alerts get sent for 24-hour periods starting and ending at midnight. Running the daily alerts will send all news from the start to the end of yesterday. Weekly alerts will send all news for the 168 hours ending at midnight last night. It won't send any alerts about news added on the same day that you run the script.
Note that OpenBlock does not remember which alerts have already been sent, so you should not send daily alerts more than once a day, or weekly alerts more than once a week -- or your users will get duplicate alert messages.
Disabling Email Alerts entirely is easy. In your settings.py, just remove "ebpub.alerts" from settings.INSTALLED_APPS. (You can copy the setting from ebpub/default_settings.py and modify it.) This will remove the alerts sign-up links from all OpenBlock pages.