In response to the congestion of several independently-run tournaments, Blizzard has announced the 2013 World Championship Series (WCS).
Basically, the tournament will operate in three major divisions: North America, Europe, and South Korea. Each region will run their own tournaments in partnership with local tournament organizers and eventually culminate in a global championship using the top-ranked players from each region.
Major League Gaming (MLG) will produce North American events while Turtle Entertainment (ESL) will handle European tournaments. South Korean events will be co-produced by GomTV (GSL), OnGameNet (OSL), and the Korean eSports Association (KeSPA).
Twitch will handle the broadcasting of all events, providing ad-supported 720p streams to all spectators. Presumably, higher resolution and ad-free streams will be sold by the respective event producers.
The first matches in the WCS will begin on April 4 with the GSL Code S bracket.
With this move, Blizzard is providing some much-needed structure to the tournament scene in StarCraft II. Until now, several tournaments would overlap or run right up against each other, allowing players no time to travel or adjust to new time zones.
Additionally, the lop-sided nature of global competition would often encourage good players to drop out of more competitive tournaments to pick up easier winnings in others.
By enforcing regional rankings and forbidding simultaneously-running tournaments, Blizzard hopes to establish the WCS as the premiere showcase for StarCraft II talent and provide viewers with the best games possible.
For the nitty gritty on the tournament details, check this post on Battle.net.