Empty /home directory, and I can't delete it?
it is set up by the system for scenarios with network home directories, which are mounted at /home. we use network homes for a number of our Mac desktops, and, in our case, if a user has a home directory specified in Active Directory, and the AD plugin is set to use it, it will mount under /home. 

my guess would be that the system doesn't allow it to be deleted because of that (at minimum).