I have been wondering how this is possible (i.e. how this works internally). When you want to mount a directory you have to be root.
sudo mount /dev/something /mnt/somedir
I know you can get around that by adding a line in fstab.
Now, I'm wondering how come if I insert let's say an usb stick and select it from within Dolphin (KDE's filemanager), it mounts it without the need for a root password and gives me write/read access to what it has mounted? I'm guessing it is using dbus to monitor for new devices. I don't see how (when it knows there is something it should be mounted) it can mount it without the need for root. I haven't yet figured out how to manually mount some device without root and maybe I can learn something from how Dolphin does it.