Time-sharing is a method to allow fast response for interactive user applications.

To provide an architecture that can be customized for user specific applications and interfaces.

They are used for user applications, server processes and operating system settings.

And where would you draw the line at "user application"?

Is an office suite a "user application", or should that be system wide?

Yes, an office suite should be a user application.

Physical data independence deals with hiding the details of the storage structure from user applications.

But for most of these sites, user applications aren't featured on the site prominently.

However, since there are no user applications that allow meaningful input to the system, not much can be done with it.

Commands are not limited to systems level concerns and can be drafted for user applications as well.