Oh um I am not sure about that whole Microsoft comment, seems to me user, groups & permissions are pretty much the same to me. Granted in some finite details perhaps some differences but to the end user not much. To the Admin yes because he has to CLI everything.
Linux is derived (conceptually, at least) from unix. Unix is a multi-user OS. Thus permissions at the user, group, and global levels make sense for controlling file access. Microsoft has--traditionally--written single-user systems. On a single-user system (and especially when the single user is the de facto, if not de jure, superuser), file permissions don't really mean anything.
Hence my comment that MS doesn't understand permissions. They've been consistently omitted from MS written file systems.
The result is that if you mount an MS-designed file system (FAT, NTFS...) on a unix/Linux system, the file permissions have to be kludged externally to the file system.