I noticed that this only works if the site is 'Online'.

If a site is 'Offline' (say for maintenance or in beta development), the Iphone app says the website does not support Notifier.

I'm not sure if this is a Bug in this module, a bug in the app, a limit of Drupal in 'Offline' mode or a feature request.

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Drupal 6.15 (User 1 login)
Drupal Notifier 6.x-1.2
Iphone App 0.2