The 2011 Worldwide Developers Conference filled up within just 12 hours, perhaps due to its rumored double-focus on "the future of iOS and Mac OS," as spoken by Apple senior vice president Phil Schiller early Monday morning. Earlier in the day, several Mac and iOS developers had joked about the conference selling out early on Twitter; by 4PM PST, the joke had become reality: the "Buy now" button featured so prominently on Apple's had been replaced with a graphic proclaiming the conference's "SOLD OUT" status.

While WWDC has been selling out before its opening day , this year's speedy turnaround is particularly unusual: Apple's conference last year in 2010 to fill to capacity, while it took to sell out. As previous conferences have primarily focused on either Apple's mobile or desktop OS, but never both, it's likely the promised double-whammy of available tracks for both the Mac and iOS attracted a much larger pool of developers than last year's iOS-centric conference.

For those lucky enough to grab a ticket, WWDC 2011 and feature over 100 technical sessions for both iOS and the Mac OS on Application Frameworks; Graphics, Media, and Games; Developer Tools, Internet and Web; and Core OS, in addition to its signature keynote event.