This was a project I started in 2010, which is now archived. In January 2012 I made a short screencast introduction to Kanso, which demonstrates some of its features:
Kanso saw a number of real-world uses cases, some of which I was lucky enough to work on, including projects to collect healthcare data in Africa and a First Nations dictionary project in the Northwest Territories. Kanso's ability to quickly develop software with seamless offline capability proved invaluable.
The features that enabled CouchApps to work on CouchDB were mostly accidental. For a while commits would land in CouchDB to better support this technique, but eventually the CouchDB team understandably wanted to focus on the project's core database capabilities.
Ultimately, I joined other CouchApp developers on the Hood.ie project: a separate application layer that could sit in front of CouchDB and provide capabilities to extend the original CouchApp technology.