Warning, this is all going to sound more pretentious than I am usually comfortable being: It seems like this happens a lot, there is a sort of cycle, though I feel like it has changed and something new is forming. A lot of sites that start as reliable bastions of intellectualism or emerging cultures eventually go mainstream and slowly become diluted. TED hit this point probably about a year ago and quality will go downhill it seems. Similar things can be said for reddit, and other sites. Perhaps this is a reflection on the ethos of the web 2.0. By being democratic, having content created flow from the bottom up, once a site becomes too bit, it will start playing to the common denominator. Or perhaps I need to have more things to do at work and less time to reflect on the Internet. PS. This TED talk is now officially meta.
It's no one's fault but TED's, because they get to pick and choose who speaks. Reddit's admins don't have this privilege, and MK and the others don't really either. The admins have influence, but they don't have complete control. TED caved to greed (i.e. page views), and I have nothing but contempt for them. I sympathize with Reddit's decay, and I will for hubski if that happens, but not for TED, because they brought it on themselves. There's no good reason it should have happened, or should be happening, to TED.
This originally happened at TEDx which are local events put on by local groups, again reflecting a democratic sense of content creation. TED had the choice of how to highlight the video, but I'm guessing that it probably already was getting a lot of views before they even started to highlight it.