The namespace is part of a Personal Data Account. It identifies where the application will have read and write access. It is similar to a directory or folder in your operating system. All operating systems profile access to a base user folder in which users can read and write their data. Usually that folder has many subfolders, created by the operating system. Similarly, a namespace is the base folder for the application. The application has read and write access and is able to structure the data in subfolders.