Original: In December 2007, it was announced that Activision would merge with Vivendi Games, which owns fellow games developer and publisher Blizzard, and the merger would close in July 2008. The new company is called Activision Blizzard and is headed by Activision's former CEO, Robert Kotick.
Simplified: It is going to merge with Vivendi and will be called Activision Blizzard.