Tickets for the annual Worldwide Developers Conference (WWDC) went on sale at 7:00pm on Thursday 25 April and were sold out within two minutes.
In 2011 tickets sold out in 12 hours, 2012 sold out in 2 hours and now 2013 has sold out in 2 minutes.
WWDC has space for 5000 delegates every year. There have been calls for Apple to increase the number of delegates but then there would be significant problems as Apple provides personal support for developers during the conference and would be unable to provide enough support for more delegates.
In the last few years Apple have used WWDC to announce updates to OSX and iOS as well as release new products. Apple is expected to give a preview of iOS 7 and an update to OSX but rumours of any product launches are very slow despite the high expectation of an iWatch or Apple TV.