Blizzard's said it won't be hosting BlizzCon in Anaheim, California this year due to the company's "jam-packed schedule."
The full quote provided by Blizzard was: "In light of our jam-packed schedule, we've decided to hold the next BlizzCon in 2013."
The Battle.net World Championships, which typically take place at BC, will still take place, however. Locations on that and BlizzCon 2013 will be announced soon.
Blizzard currently has Diablo III for an early 2012 launch, as well as the currently undated StarCraft II: Heart of the Swarm and the next World of Warcraft expansion Mists of Pandaria, plus upcoming MMO Titan.
In fact, Blizzard VP Rob Pardo said two years ago that Titan wouldn't be announced until this year at least. BlizzCon, for all intents and purposes, would very likely have been the place that unveiled it.
Last year's BlizzCon seen new Diablo III and Heart of the Swarm content unveiled, as well as Pandaria's formal announcement.
We've emailed the company for a more detailed statement.