iD developer here. I did a series of posts on the architecture of iD that folks here might find interesting:

http://www.mapbox.com/osmdev/2013/02/26/id-architecture-part... http://www.mapbox.com/osmdev/2013/02/27/id-architecture-part... http://www.mapbox.com/osmdev/2013/02/28/id-architecture-part...