Google Glass isn't yet publicly available, but it already has apps functional enough to be demonstrated to a live capacity crowd of developers and curious folks in a ballroom at the South By Southwest in Austin, Texas today.

Timothy Jordan, Google's senior developer advocate for Glass, showed off the augmented reality spectacles running apps for Gmail, Evernote and the New York Times in a highly technical presentation that covered some guidelines and even some of the code involved to develop apps for Glass.

Glass apps will center around the use of what Jordan called "timeline cards," which seem to be similar conceptually to the cards used by Android devices running Google Now. Timeline cards could be text, images, video or "bundles" of expandable data that contain multiple timeline cards that can be expanded by tapping on the side of the device.

Jordan also noted that developers should design apps specifically for Glass rather than attempting to "port" existing tablet apps. He demonstrated the New York Times app for Glass as an example. The app delivers new headlines with an image and byline and the option to have Glass read the story to the user.

The Glass Gmail app works in a similar fashion, with a subject line and photo of the sender popping up in the display. To reply to a message, the app takes dictation and then sends the text.

Demonstrations of apps for Evernote, Skitch and the social network Path all showed similar basic functionality, as well as the ability to handle and share photos and other media.

There were no new earth-shattering announcements about Glass' capability, but we're beginning to get a better idea of how it will work. First, it seems the idea is to move some of the things we're accustomed to doing on smartphones and tablets on to the new platform.

Jordan emphasized over and over again during his presentation that the key to good Glass apps is making them as unobtrusive as possible, so that any notifications or other actions can be dealt with easily or completely ignored without degrading the experience.

Google recently held Glass hack-a-thons in San Francisco and New York for developers to build enthusiasm for the new augmented reality platform that the company says will be available for consumers to purchase by the end of the year.