Permissions regarding items (posts, Documents and Tasks) are based on where the item is shared to, and who has access to the places you're sharing the item to. In the case of sharing a post, Users who have access to the post will see the entire discussion within the post, from when it first started. Internal and external Users are also covered towards the end of this article.
Sharing an item directly to another User
If you share an item to another User, they will have access to see this item.
Sharing an item to a Group
Any Users who are members of the Group will have access to the item that has been shared to the Group.
Sharing an item to a Project
Any Users who are members of the Project will have access to the item that has been shared to the Project.
Sharing an item to a Customer
Any Users who are members of the Customer will have access to the item that has been shared to the Customer.
Sharing an item to multiple contexts, for example a Group and a Project
Items can be shared to more than one context, for example a Group and a Project, or a Project and a Customer, or three different Groups. When this happens, all the Users who have access to the context the item has been shared to, have access to the item.
It is important to remember that even though the single post is now shared to multiple contexts, the Users within those places are still segregated from each other. In the example below, the Users in the Project cannot see other items that are in the Group. Nor can Users in the Group see other items in the Project. The item in question is simply visible in both places. It does not bind the two places together.
The same is also true if you share a post to a Group and also a user who is not in that group. Although the user has access to that particular post, they do not have access to any other discussions with the Group.
The same would also be true of sharing a post to a Customer and a User who does not have access to that Customer.
Sharing one context to another
In the section above, we established that sharing a single item to a different context does not bind those two places together. It is however possible to share one context to another, to enable other Users to access the items within that context. The sections below outline how this works.
Sharing a Project to a Group
Sharing a Project to a Group means that everyone who has access to the Group will have access to the Project.
Sharing a Customer to a Group
Sharing a Customer to a Group means that everyone who has access to the Group will have access to the Customer.
Sharing a Project to a Customer
Sharing a Project to a Customer means that everyone who has access to the Customer will have access to the Project.
Sharing to external Users
External Users only have access to - and visibility of - the Groups or Projects they are invited into.
External Users interacting with other Users within your community
External Users can only interact with the other Users who are members of the Projects or Groups they are members of.
External Users interacting with Groups shared from Projects
If a Project is shared to a Group, an external User can post or share to that Group - but not directly to the members of that Group, unless the external User is linked to those members in another way.
Members of the Group can however interact directly with the external User if required, and share a post or document to them.