It was reflecting poorly on TED’s previously good name. They decided to do something about it. The editor of TED.com and the TEDx Director issued a letter to organizers of TEDx events.
It says in part:
In light of a few suspect talks that have come out of the TEDx movement — some of which we at TED have taken action to remove, some being examined now — and this recent thread on Reddit, we feel it is important to reach out to all TEDx organizers on the topic of bad science and pseudoscience.
Please know this above all:
It is your job, before any speaker is booked, to check them out, and to reject bad science, pseudoscience and health hoaxes.
The letter goes on to give guidance on how to tell a bad topic and avoid booking such a speaker. They cite sites like Science-Based Medicine as good sources to help vet talks. And some lists of features characteristic of pseudoscience. They can probably consult with their local skeptics group to help as well.
Some of the previous talks have been taken down from the web site. Even better would be to NOT allow those types of speakers to begin with. Of course this would not preclude talks on other topics, just particular to those making a testable claim.
Phil Plait, a TEDx speaker, loves the letter and blogs about it. TED to TEDx: How to avoid bad science in talks.