They say to put this entry into your sudoers file:
myuser myhost=/usr/local/libexec/xfsm-shutdown-helperWell that's just geek speak for what you most likely want which is something more like this:
myuser ALL=NOPASSWD: /usr/sbin/xfsm-shutdown-helperIf you do not specify NOPASSWD then you will be prompted for a password when you shutdown ... who want's that? And /usr/sbin/xfsm-shutdown-helper is the default for the 4.4.2-2 version of the xfce4-session package in debian (sid) at the time of this blog entry.
Hope that helps.
P.S. You'll get great extra credit with me if you can tell me why this link does not go to the right anchor on the page it refers to when using firefox version 188.8.131.52.