From Diablo Wiki
The Blizzard World Wide Invitationals was originally a way fro Blizzard to celebrate the Asian interest in StarCraft and WarCraft III, and held in Korea. The first of these events were relatively modest, but in April 2007 StarCraft II was announced at the WWI event in Korea, and the size of that event was naturally considerably larger in scope. In 2008 the event moved out of Asia and into Europe, Paris, as some "BlizzCon Europe" model. This event was also made with a huge scope, and was the host of the Diablo III announcement.
There has not been a WWI since 2008, with only Blizzcon and sometimes Gamescom offering fans a chance to get their hands on playable demos of Blizzard's titles in development.