Can't wait to get my Pixel and see how useful this is.

Reshared post from +François Beaufort

The new Chromebook Pixel is the first Chrome device that has the ability to perform some limited Wi-Fi functions during sleep, for example connecting to known hotspots for faster connection after wake up. Of course, you can manage whether this feature is turned on or off in chrome://settings.

This new setting is the first feature of an experimental project codenamed Lucid Sleep¹. Its goal is to create a hybrid power state that could wake up a Chromebook from a suspended state to perform some work. Potential tasks include:
– Associating with a known Wi-Fi access point that has just come into range
– Updating user data in response to a received push message²
– Synchronizing with app servers at the request of an app
– Performing system maintenance like trimming SSDs or checking the battery level

Please refer to the Lucid Sleep design document¹ to understand how Linux Kernel, Power Manager, Shill Connection Manager and Chrome browser work together to coordinate Lucid Sleep.

¹ https://www.chromium.org/chromium-os/chromiumos-design-docs/lucid-sleep 
² http://updates.html5rocks.com/2015/03/push-notificatons-on-the-open-web

Source: https://codereview.chromium.org/1065043003