One thing we all agree is a focuse on learning "Google Cloud Messiging" aka GCM. To prepaire for ADD7 here are Google's own background documents, API and sample code for GCM:
GCM is part of the "Google Services" thus this is the highest level:
Google Cloud Messaging (GCM) for Android:
GCM Demo Application:
Making the Most of Google Cloud Messaging ( GCM ) From Advanced Android Training:
Please add related information to this theead so that durring ADD7 we have everything in one place.