1. Go to your favorite TED talk page, such as this one by Hans Rosling.
2. Look under the video window where it says 'Subtitles'. Select English, and think of your hard-of-hearing friends and/or those for whom English is a second language.
3. Then try any language that takes your fancy. (Some will show up as blocks unless your computer has their font installed.)
4. Click the red "Interactive Transcript" link at top-right of page, then click any word in it and see what happens. This transcript is searchable by Google, so it will be possible for people to find specific comments that speakers have made and go straight to them.
5. This page explains it all and shows how different language communities are already responding (and how you, or someone you know, could contribute)
In a year's time we might have 500+ talks translated into 100+ languages. That wd be 50,000 individual translation projects, each of which takes hours of work, an impossible task to achieve any other way. Any crowd-sourcing project will no doubt generate the occasional screw-up, but we've been amazed at the dedication and capability of the volunteer translators who've contributed so far.
My colleague June Cohen and her web team, building on the dotSUB technology platform, have been working round the clock on this and have pulled off something pretty miraculous: a thrilling extension of TED's goal to spread good ideas globally.