How are live tiles made in Windows 8?

Finally figured it out, these live tiles are using tile notifications as noted by others.

Here is the minimal code necessary for updating an existing default tile with a template:

1. You have to load in a template and adjust it, or produce your own XML code. See the tile schema...

   var tileXml = Notifications.TileUpdateManager.getTemplateContent(template); 
   

2. You need to create a notification, which apparently is an update to a tile.

   var notification = new Notifications.TileNotification(tileXml); 
   

3. You need to create an updater, which will provide you with methods to notify through your tile.

   var upd = Notifications.TileUpdateManager.createTileUpdaterForApplication();
   

4. If you have all this, you can send an update to the client.

   upd.update(notification); 
   

http://msdn.microsoft.com/en-us/library/windows/apps/br211386

You can use either C# or VB + XAML or HTML/JS or C++.

That was the big announcement at the BUILD conference and the whole point of WinRT (God I hope they actually are serious about pushing WinRT for more than a year).

Otherwise it would be back to the Silverlight/.Net uprising that we saw after the first preview. . .

edit

You'll first need to learn the terminology of the MetroUI. You can also find more info under Windows Phone 7.

The Live Tiles can send tile notifications. That's how the socialite tile does the facebook feed. The OS will cycle through tile notifications that you've declared. This is all in the basic Tile sample and the advanced Tile sample.

Here is a link to all the samples from the BUILD event.

Start here for a step by step walkthrough of the platform. I would start there if the reference documentation is confusing.