Diablo 3's Success to Cannibalize World of Warcraft

Activision Blizzard was filled with excitement this morning when it announced that Diablo 3 had become the

. But the company failed to realize that Diablo 3's success could come at the expense of its former cash cow, World of Warcraft.

"The numbers were pretty impressive, and it's clear that they hit a home run, selling a lot more copies than I modeled," Michael Pachter, the Managing Director of Equity Research at Wedbush Securities, told Benzinga. "I don't think people will quit WoW to play this, they are completely different experiences, but do think that WoW hours will suffer for a while. Remember, 1.2 million copies were given away to WoW subscribers who renewed for a year in advance, so they won't quit." Activision Blizzard

is currently up more than 2%.