Difference between “cult” and “religion”

In a Fark thread discussing a particular modern religion – let’s call it “Celebritology” – someone made a good statement that once and for all clarifies the difference between a  “cult” and a “religion:”

“The difference between a cult and a religion, is that a cult has a guy in charge of everything, who knows it is all made up and a big lie.  In a religion, that guy is dead.”