I looked into this a while ago, and it seems like GAE still doesn't have a real way for the server to push to the browser (Comet). There's a ticket open for it

I looked into this a while ago, and it seems like GAE still doesn't have a real way for the server to push to the browser (Comet). There's a ticket open for it (http://code.google.com/p/googleappengine/issues/detail?id=377 http://code.google.com/p/googleappengine/issues/detail?id=37...), and it's a feature that's "on deck" (http://code.google.com/appengine/docs/roadmap.html http://code.google.com/appengine/docs/roadmap.html), but who knows when they'll get around to implementing it. As I'm sure you know, regular polling is usually too slow for a game, and counts against your app engine HTTP request quota.