Drupal Commons: notify all users on creation of new group In Drupal Commons (D7) I'd like to have all users notified by email when a new group is created. 

Is there a way to do that?
You can use the Rules module and set it to fire an action, when a group is created. 

CVS Instructions
You could also implement this User register notify

But since Drupal Commons uses Organic Groups
you might be able to use this Organic Groups Notifications
but take a look at the Rules module and Flag module. 

best regards