After the first couple of ones that were public and on the internet, the usual self-promoting psychobabble-spouting androids moved in and now it's entirely worthless. Someone spins 30 seconds worth of insight out for half an hour, and you still somehow feel stupider when you've finished watching it.
In one of the recent Gladwell threads, someone on here coined the phrase "insight porn". TED is basically insight dogging.
EDIT: to be fair, if TED is insight dogging, this place is a sticky floored insight dungeon in some godforsaken soho basement...