Microsoft said yesterday that this year's conference should be a big one, with more details of Windows 10. The company showed off new consumer features of the upcoming OS (which will be a free update to Windows 7 and 8.1 users), as well as its HoloLens augmented reality device.
The quick sellout has become commonplace for these developer conferences, so much so that Apple and Google have had to set up ticket lotteries so as to avoid their websites being crushed and to make it fair for people in awkward timezones. Both companies, as well as Microsoft, have balanced that by trying to stream all the sessions as they're happening.