Phil Plait discusses ("TEDx Talks: Some Ideas Are Not Worth Spreading") a public letter from the TED organizers to their derivative TEDx community: "A letter to the TEDx community on TEDx and bad science". I have criticized TED in the past for promoting Elaine Morgan, who gave a TED talk on her ideas regarding the aquatic origins of human adaptations. Although TED provides a platform that has enabled some scientists to bring valuable work to a broader public, many TED talks have promoted ideas that have either quickly proven wrong (bacteria making DNA from arsenic) or are dismissed for good reasons.
Plait shares his personal experience and gives a good accounting of how skeptics should approach untested ideas:
GOOD: It makes claims that can be tested and verified, and It is backed up by experiments that have generated enough data to convince other experts of its legitimacy.
BAD: Has failed to convince many mainstream scientists of its truth, and Comes from overconfident fringe experts.
These are then followed by a series of red flag topics and behaviors that, again, should serve as a warning that what the speaker is saying may not be legit: They are selling a product, they claim to have privileged knowledge, they demand TEDx presents both sides of an issue. (That last one is a biggie: In many cases there arent two sides unless one side is reality and the other is nonsense.)
I don't know if TED will be able to resist the allure of pseudoscientific pitch artists in the future. After all, it is not a "science" conference, and many of the "ideas worth spreading" seem uniquely to appeal to a certain group of woo believers. But this letter is helpful and gives the hope that they will be careful in the talks outside their main conference that they choose to promote more broadly. Now, if only we could get the History Channel to adopt a similar attitude...
UPDATE (2013-12-31): Looking carefully through the open letter from TED central ("A letter to the TEDx community on TEDx and bad science"), it does make clear that pseudoscience and medical hoaxes have real-world consequences and that organizers have a duty to weed out potential speakers who offer pseudoscience arguments.
Vetting your speakers is hard work, and can lead to uncomfortable moments. But as TEDx organizers, your audience’s trust is your top priority, over and above any other personal or business relationship that may have brought this speaker to your attention. It is not your audience’s job to figure out if a speaker is offering legitimate science or not. It is your job.
That is a valuable statement emphasizing the position of the TED community is not a free-speech forum, and speakers do not have a "right" to have their pseudoscience views aired by the organization. I still wonder why TED has promoted talks by noted pseudoscience quacks in the past. After all, the central organization pushes only a fraction of the videos from TEDx events into the queue of talks that will be widely circulated, and they have chosen some real doozies.