I've installed the Notify module to see if its a good module to allow users to be notified of new content. There doesn't seem to be a 'default' setting that will apply to new user accounts. ;(

http://drupal.org/project/notify

1. Extract the notify module directory, including all its subdirectories, into your drupal/modules directory.
2. Enable the notify module on the administer >> modules page. The database tables will be created automagically for you at this point.
3. Modify permissions on the administer >> access control page.
4. Go to administer >> settings >> notify and modify the settings to your liking.
   Note: e-mail updates can only happen as frequently as the crontab is setup to. Check your crontab settings.
5. To enable your notification preferences, click on the "my notify settings" on the "my account page". Or, similarly go to another user's account page at user/<user_id_here> to modify his or her personal settings.
6. Additional options can be set at administer >> users by clicking the "notify settings" tab.