So, I've read this, the announcement on XPrize, and a few articles, but I can't for the life of me figure out what the contest is, or what they want people to build...
Notice how that old link to http://www.xprize.org/ted now redirects to the IBM Watson prize. Which itself was vague. "this challenge requires an AI to form an opinion and support it with facts". I wouldn't be surprised if there's almost no link between the two.