Short answer
A Private Index is created and managed by you or your organization. A Shared Index is created by AskTuring and available to all users.
Full explanation
Private Index:
Created by you or your organization.
Content is controlled entirely by you — you decide what to upload, edit, or delete.
Only members you explicitly invite can access it.
Supports custom Semantic Maps, folders, and permission settings.
Shared Index:
Created and maintained by AskTuring.
Available to all AskTuring users.
Cannot be edited, but all users can search it.
Often contains public or reference materials (for example, “Big Beautiful Bill” — the full text of Public Law 119-21).
Tips
Use a Shared Index for quick reference to preloaded content.
Use a Private Index for secure work with your own organization’s documents.