Cult
The term cult usually refers to a social group defined by its religious, spiritual, or philosophical beliefs, or its common interest in a particular personality, object or goal. The term itself is controversial and it has divergent definitions in both popular culture and academia and it also has been an ongoing source of contention among scholars across several fields of study.More at Wikipedia
Seems to have a broad definition. If I were to use the word loosely, I could define YouTube channels as being a cult, based on their following. Has the word become too loose to be dependable as an adjective?