Dominant forces in social media come and go, but one thing Twitter has always had going for it is the immediacy factor. twitter does its best to be a required second screen, so of course it would put a big effort toward as huge of a live event as the World Cup. As it did for the 2010 World Cup, hash flags for participating countries and official hashtags to be used in match centers help make twitter an effective place to talk about the World Cup in real time.
The commercial twitter came up with is awful generic, using scenery and street football to set the proper mood for the tournament. It's not the effort that ESPN can put forward with national team shirts and American Outlaws, but it gets the point across.