People who need a flight can create a contest and then flight hackers compete against each other to find them the best deals/flights. This RTW contest was an experiment to see how far our hackers could go, and considering a RTW itinerary usually costs $4k+, their results are pretty impressive.
Sorry, I should have clarified. I wasn't able to click to actually see the itineraries created even though there are "View Details" links. The other links I tried to click on the page also just hung. I guess all the hn traffic took them down.
Edit: I see your other post above now with the cities! Thanks!!