When you complete a shared task, a notification pops up asking if you would like to complete it only for you or for all other shared users. You can choose to either mark this task as complete on your list or on all members’ lists. If you choose ‘Everyone’, all the members will receive a pop up notification. If you choose 'Just mine', it will be completed on your list and you will be removed from the shared task. The other members will receive a notification that you have left the task in their Notification Center.