This project we started around 3 years before this publish date. We wanted to create an app that can help people form transient groups with common goals.
So were able to successfully create chat application using GCM messaging framework. We used XMPP protocol for chat messages. A full GCM implementation requires both client implementation and server implementation.
Check out this tutorial for details.
We stopped our semi anonymous social networking after facing technical challenge in keeping up the XMPP server all the time. (The cloud services were not so popular and cheap at that time).
We have decided to open source this project at AnonymousChatApp
Please write to us if end up creating some interesting chat app.