I modified the python example to add XMPP support and created this website. You can access this on https://bareboneglass.appspot.com/ and it's source code is on https://github.com/DeqingSun/bare_glass_app.

It's quite similar to the python example. When you click "Add a card you can pin and reply", a card will be inserted into your timeline and that card has an option to reply. Also you can pin that card for easier access. You can also add your XMPP address to server by typing your address in the text field and press "Add XMPP address". If you don't have one, you can find a provider on http://xmpp.net/ and register an address.

Before you write any code, you can try this service by logging in your XMPP account on your computer with a client like Psi. All messages replied to that card will be forwarded to your XMPP address and you should see that on your computer. On your computer side, you can send messages to "[email protected]". You can send "/echo something" to test if this service is working or send "/push some message" to send a message into your timetime for you to view on your Glass.