The idea is that the more you interact with the site (taking an "entrance exam", uploading posters for a contest and "liking" Facebook pages) you can help to move the site's progress bar. The more the bar is moved the more exclusive content (artwork, posters, videos, music and more) is revealed on the site. At the moment the site's progress bar has been moved 30 percent. You can also win an Alienware M11x laptop if you win the site's propaganda poster contest.
Gallery: StarCraft 2 Screenshots