Departments and Rights are used to control who can see and what they can do with specific documents in the system.
Boost allows for very fine grained access control to information. This control is achieved through the concept of departments and rights.
A department is a group to which a user can belong. Typically, you could create departments for Human Resources, Legal, Marketing and Sales, Operations, etc. For a smaller company, it might be sufficient to only use Operations and Administration.
Once you have defined department, you can specify per document which departments are allowed to access these documents. You can even enable of disable specific modules of a document for certain departments.
It is also possible to create an anonymous department and give certain documents or parts of documents access to the anonymous department. This allows non users to create forms without requiring a Boost account. This functionality is very handy if you want to create public fomrs like questionnaires, job applications, customer satisfaction forms etc.