What exactly does USB persistence mean? I'm not sure if I'm doing something wrong or if the USB persistence is not working.

So far I have have followed the instructions to put the 64bit (kali-linux-1.1.0a-amd64.iso) on to a USB drive but it's working as expected. I went into the persistence boot option and created the mount dir and mounted the newly created /dev/sdb3 partition and created the persistence.conf file. When I reboot the setting I change are set back to "default" and even the dir I created for the mount point is gone.

Am I missing something or is this just not working? Are they steps I need to take on each reboot to protect such changes?

Any help would be greatly appreciated.