[richardwhiuk]

Yes, and I believe both GCM and APNS perform cross-app notification coalescing, whereby a low priority notification (e.g. a news article, or some other content update) will picky-back on a high priority notification (incoming call, text message).

This is extremely valuable in reducing power usage.

(Notifications both exhibit radio usage, but also will typically turn on the display, which is a huge battery sink)