Heard this quip somewhere:

    If, on appropriate occasions, the members tell, enjoy,
    trade, and/or devise transgressively funny jokes about
    their denomination, it’s a church.

    If such jokes reliably meet with stifling social
    disapproval, it’s a cult.

This works for TED as well. I find some TED talks to be really useful. Others not so much. Just like every other group gathering whether it be a conference, educational institution, club, or whatever.

Think critically about everything.