Mindblowing stuff! I guess I have to make the distinction between the content of the talks presented on the site and the website itself, because the real credit for the amazing content must go to the varied and interesting people who deliver the talks. Having said which, the talks are given precisely because TED runs conferences and invites these people to speak in the first place.
TED stated mission is to spread ideas that can change lives and attitudes and they are clearly doing a great job. I just spent ten minutes listening to Charles Limb give a talk on how the brain produces creativity. One of the most astounding parts of the talk was listening to a guy called Keith Jarrett playing piano (improved). To mind there's some debate that there is a huge amount of creativity going as opposed to randomized selections under the auspices of a massive repository of musical knowledge - still, it's remarkable.
TED delivers inspiring talks on a huge range of topics, not necessarily science but pretty much all spheres of human endeavor - technology, design, art, culture and so on. The website itself is a nicely presented platform for spreading the talks given in the conferences - it's like the open source movement for ideas.
Want to listen to the most influential thought leaders of our time? This is the place.