How is it different from team speed skating?
Unlike traditional long-track or short-track speed skating, in which four to six skaters at a time race around the oval in a time trial format, mass start involves up to 24 skaters facing off against one another at the same time in a mad dash to complete 16 laps the fastest. As you might imagine, things can get a little bit crowded and crazy, and it basically becomes the closest thing you'll ever see to a roller derby on the Olympic stage.
Winning involves a bit of both short-track and long-track strategy, as there are three sprint laps throughout the longer 6,400 meter race -- a "race within a race" if you will. Specifically, laps 4, 8, and 12 of the 16 are the "premium" or sprint laps, and the first three skaters to finish each of those individual laps are awarded points. However, points aren't what earns a skater a medal, because to get on the podium you have to cross the finish line at the end (after the 16th lap) first, second, or third (makes sense, right?). The points awarded for the sprint laps come into play to help rank the other finishers.