Presentations also hammered home how developers can make money off their apps. If they sell through the Windows store, they reap $75% of the take for the app up to $25,000, then they make 80%. Also, the developers' kit enables setting up a tile within the app that can host an advertisement that the developer can sell and change.

The apps can also support in sales within applications -- like buying a level upgrade for a game while logged into the game.

Ballmer showed how changes made to a document in OneNote and stored in SkyDrive show up when accessed by other devices. Similarly, changing the photo on the lock screen and storing that to SkyDrive appear on the user's other Windows 8 or Windows Phone 8 devices.

Ballmer says the launch of Windows 8 and Windows Phone 8 this fall when considered as a single event represent one of the top three events in Microsoft history, the other two being the release of the IBM PC with a Microsoft operating system and the launch of Windows 95.

Getting developers to create a broad inventory of apps that showcase Windows 8 new features is key to Windows 8 success, so Ballmer walked the crowd through them: