Google has announced that while not quite ready for the stable channel, Rich notifications will begin appearing in the Beta Channel of Chrome for Windows.
Chrome and ChromeOS already support basic notifications which can appear outside the browser window. Rich notifications allow Chrome apps and extensions to show notifications that contain far more information and interactivity outside the browser window than these basic notifications.
Functions such as the ability to reply to emails or calendar reminders from the notifications are included as is the ability to mute notifications at any time.
To get access to rich notifications you’ll need either the latest Chrome Beta on Windows or be on the Developer channel build of ChromeOS. Google will also be rolling rich notifications out to Mac OS X and Linux soon.