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.
Strangely, this guy does not even promote his book. His book completely changed my mental approach to language learning. I highly recommend it to anyone who is learning a language.
A starting point for further reading: http://tedx.tumblr.com/post/37405280671/a-letter-to-the-tedx...