Your Portal Account was purchased with a initial number of paid-seats, and additional paid-seats can be added at any time.
You have an unlimited number of non-billed seats in your Account.
* denotes a special use-case, use only when instructed by the Site Admin.

There are Account level permissions (paid-seats), these Users have their access level across ALL Workspaces.
Moderator - can upload, edit and delete any file or folder. can invite other users to Workspaces, can invite Users to an individual file or folder, and edit all comments within a Workspace.
Collaborator* - only can upload, edit and delete any file or folder.
Creator - can view previews, print and download files. can upload files to a folder or their assigned Workspace, can only delete files which they created. can view and add comments to files, folders, and messages. can post messages to their assigned Workspace.
Downloader - can view previews, print and download files in their assigned Workspace.
Printer - can view previews and print files (download prohibited) from their assigned Workspace.
Viewer - can view previews of files only (print and download prohibited) from their assigned Workspace.

There are Workspace level permissions (non-billed seats), these Users have their access level within their assigned Workspace.
Creator
Downloader
Printer
Viewer

Any level User whom is Invited to 3 or more Workspaces additionally constitutes a paid-seat.