I upgraded to 12.10 and I'm excited to use the web apps feature but it's not working! I did everything by the book:
sudo add-apt-repository ppa:webapps/preview
sudo apt-get update
sudo apt-get install unity-webapps-preview
I integrated my online accounts and installed Gmail web app on Chromium (version 22.0.1229.94). I got in my password and the magic didn't happen. There's an extension added to Chromium but no Gmail in messaging menu and no Gmail icon on launcher. The same thing for Facebook and YouTube.