The closest site I could find for Google related questions is Android Enthusiasts. I would like to ask a question about Google Voice & Hangouts. It does have an Android app but it's not a question about the Android OS; only the app. Is there a more appropriate site than Android Enthusiasts to ask such a question?
While Google services are generally web-based, virtually anything they put on a smartphone is a native app, and would thus be off-topic at Web Applications. You'll be better off at Ask Different or Android Enthusiasts.
That said, if you want to ask about the actual web interface for Google's myriad apps, then Web Applications is the place.
In addition, aside from Voice, Google App Engine Python questions are, I believe, on Stack Overflow with the google-appengine-python tag. Google announced a while back they were outsourcing some elements of free support to here. I see some other
google-app* tags too.