TEDx conferences are run by people peripherally related to TED, if at all, and they have a long and unfortunate history of giving a platform to frauds, hoaxes, and charlatans. I think it's gotten a bit better after some particularly bad talks came to light in late 2012, but quality control is still frequently lacking.

A starting point for further reading: http://tedx.tumblr.com/post/37405280671/a-letter-to-the-tedx...