Outlook folders can be shared with other uses, such as your Inbox, Calendar, and Contacts. You can choose the level of permissions you grant individuals or groups. For example, a Principal could share his/her calendar with their building staff and only give them Reviewer Permissions, which would allow building staff to read the calendar appointments, but not add or change appointments. The same principal could also give Editor Permissions to his/her secretary, so the secretary could add, change or delete appointments in the principal’s calendar. To share an outlook folder, right click on the folder, choose properties, and then choose the permissions tab.
Users can also give delegate permissions to others. This allows the delegate to send email on behalf of the user granting delegate permission. The delegate can also be delegated to receive, answer and send calendar notices for the user.
Most of the time, sharing allows the user to do what they need. Delegate permission should be used sparingly and only when the user wants someone else to have the power to communicate on their behalf.