qr code is about easily passing data to your smart phone.
The most common application is give url to your phone. android 2.2 got a feature to push links from chrome to android phone.
with qrcode, you can do it from any browser to any smartphone.
One could write an plugin for that... one js including all what is needed. display a small icon on the page. when the user click on the icon, a large qrcode open, and the user can scan it and go on on its phone.
backbone is super nice, i wont be the one saying otherwise. It isn't the same scope tho. It does event emitter and much much more!
I like micro frameworks (aka tiny libraries) because it is standalone and so small you can easily maintain it yourself if needed. So it is less an actual dependancy.
This is a little tool i did this weekend for another project of mine. It may be usefull to quickly embed ace if your project without worrying about namespace collissions.
https://github.com/jeromeetienne/webglmeeting/issues/2