A site mailbox brings Exchange emails and SharePoint documents together. For users, a site mailbox serves as a central filing cabinet, providing a place to file project emails and documents that can be only accessed and edited by site members.
What is the difference between site mailboxes, shared mailboxes and public folders?
Site mailboxes
For groups of people that are working together on a shared set of deliverables. They want to keep important emails and documents in one place.
The content is scoped to a particular project that a small team is working on. As such, all content in that mailbox is highly relevant to the team members.
User will not see a site mailbox in their Outlook client unless they are an owner or member of that site mailbox.
Shared mailboxes
A group of people is working on behalf of a virtual entity (e.g. help@contoso.com). They are triaging incoming emails against a shared inbox and responding on behalf of the virtual entity.
Integrated document collaboration is not a requirement for this scenario.
Users will usually only do this for one shared mailbox and the mailbox is added manually to the user's Outlook profile.
Public folders
Public folders hold the full body of shared email knowledge in an organization.
Public folders are a great technology for distribution group (DG) archiving. A public folder can be mail enabled and added to the DG. Emails that are sent to the DG will be automatically added to the public folder for later reference.
Documents should not be stored in public folders since they don't support co-authoring or version management like SharePoint.
