But I'm even happier to see that more people are discovering Backbone.js. After discovering it myself a few months back, it's felt equivalent to the first time I discovered jQuery after having written just plain old javascript for what seemed like an eternity. It was just a giant wake-up call to how awfully hatched together my previous apps were, and even though it's "overkill" for most of my sites I still use it anyway just to stay familiar.
For the uninformed, it's an extremely lightweight javascript front-end MVC framework (it's less than 4 kb when minified and gzipped, and just a single file to include). That immediately appealed to me. There's no complicated or overengineered new directory structure or significant paradigm switch I have adjust to, incorporate into my build system, etc. You basically just translate your existing MVC methods to the browser. Your Models are structured data that are aware of the RESTful URL where it can serialize itself to save or grab updated versions of itself from. Your Views are two-way bindings of your Models to any UI elements on the page that represent them. If your Models should change because your long-polling revealed that they've been updated, any UI elements that you've connected them to will automatically reflect those changes. And if you interact with those UI elements, and it happens to change the state or data of a Model, the connection still exists and the Model knows the back-end's RESTful URL to send its update to. The Controller ties it all together by routing deep-linkable hash URL fragments (like "#/book/1") to your existing Collections of Models and Views.
It won't provide you with megabytes of UI libraries and widgets, or overwhelm you with an insane amount of options or functionality. It's just an excellent foundation that lets you really clean up your front-end logic from what would otherwise be a chaotic soup of click bindings and callback functions over thousands of lines of code. I really want to encourage others to try it out on their next project: it's just fun to use.