Is there any difference between a cult and religion?

From what I can see every religion began as a cult. So aren't all religions just cults that didn't fizzle out? I remember reading an article that said that the only difference between a cult and religion is a century. In other words if a cult lasts at least 100 years it becomes a religion, because all the original leaders are dead, and it outlasted them.
Is there any difference between a cult and religion?
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