Parental Controls

Any thoughts about why the parental control seems to do nothing?  I did it on the "old school" control panel and it did nothing. It didn't even block pornhub. So then I logged into the "the new!" glossy version.  Turned parental controls on.  It say they're on.  And nothing.  Its not like my crafty teenager is dodging the controls. Like, pornhub is still available. Is this one of those "fake out" things that, although there is a setting, xfinity just doesn't do?