The Chrome service was announced before Google I/O 2013 in a blog post titled 'Building efficient apps and extensions with push messaging.

The GCM has the ability to send push notifications, deep-linking commands, and application data.

[11] When the developer wishes to send a notification event to a device, the process begins with an API POST request being sent to the GCM Authentication Service.

The POST request includes the GCM Registration ID, priority, optional values and links, and the information that is to be displayed on the device upon its arrival.

Upon successful verification of the GCM Registration ID and other credentials, an authentication token is returned.