Most of these have very close parallels in previous MVC frameworks, such as Rails and Apple's Cocoa. I think the biggest reason YUI3 and Backbone look more simi

Most of these have very close parallels in previous MVC frameworks, such as Rails and Apple's Cocoa. I think the biggest reason YUI3 and Backbone look more similar to each other than to those is because they're both client-side JavaScript frameworks instead of backend like Rails or desktop like Cocoa.