OTW fares were legitimate entries in this contest, but they don't start very near $2000 for hitting all six continents. I briefly checked, and would've entered one in this contest if it were that cheap. :)
Even at low season, if you price out an itinerary starting/ending in North America and hitting all six, using OneWorld's online calculator, it always comes out $3500+. You can get lower if you don't have the six-continent requirement, though.
A $2000 RTW ticket wouldn't include taxes and it wouldn't go to all 6 continents. All the prices in this contest include taxes and stop on every continent (except Antarctica).
Even at low season, if you price out an itinerary starting/ending in North America and hitting all six, using OneWorld's online calculator, it always comes out $3500+. You can get lower if you don't have the six-continent requirement, though.