WWDC- Apple’s annual developer conference for anyone who wants to stay ahead of the game when it comes to all things related to iOS and OSX development.
$1,600 a ticket. About 5,000 attendees (the capacity of the conference centre where its held). Videos and slides are made available to all registered developers afterwards (for which you pay a fee of something like $80 a year, which you need to do if you want to get apps in the App Store.) And unlike Googles I/O conference, they don't have a history of giving away free gadgets. You get admission, and that is all.
Last year, it sold out in 2 hours, when dates were announced and tickets went on sale at the same time.
This year, dates for the conference and ticket release time were announced together earlier this week. And tickets just sold out in less than 2 minutes.
If you're wondering if developers are losing interest in Apple's platforms, then the fact that 5,000 of them just collectively handed over about $8 million just to hear what they have to say *in person* might be a relevant data point to bear in mind.