The juggernaut developer behind the StarCraft, Warcraft, and Diablo franchises just announced that they're laying off 600 employees this morning. Mike Morhaime, Blizzard's president and co-founder, released a public statement on the World of Warcraft forums to clarify the need to let these employees go and which sections of the company would be affected.
In his message, Morhaime stressed that "the development teams in particular remain largely unaffected by today's announcement," that all employees leaving would be given severance packages and other benefits, and that this will not affect their plans to release "multiple games" this year. A press release sent out this morning went further, saying that "90% of the affected employees will come from departments not related to game development," and further specifying that "The World of Warcraft development team will not be impacted."
It's unclear exactly what departments are affected, however it's likely that auxiliary areas like customer support, Q&A, marketing, etc. are the ones affected.
According to a Gamasutra report on a GDC presentation by Blizzard's J. Allen Brack and Frank Pearce in 2009 told the audience that "As an organization, World of Warcraft utilizes 20,000 computer systems, 1.3 petabytes of storage, and more than 4,600 people." That number has assuredly changed in the past year and a half since that statement was made, and probably includes contractors and temporary employees—but it also only reflects a portion of Blizzard's entire portfolio of games. Even without firm numbers, we can assume that the 600 employees let go today likely represents a small percentage of Blizzard's total employees.