"In computer science, coupling is the degree to which each module relies on a number of other modules. By decoupling your application, you're able to easily extend and develop one layer without affecting the other."
Note: Remember that the architecture presented is flexible and you're free to use as few or as many of the patterns covered in your applications.
For those looking for the demo application shown near the end of the talk, the source to it can be found here: https://github.com/addyosmani/largescale-demo.
Links to articles I've written related to this talk can be found in the 'Further Reading' section.
A gist I posted with a few different ways to implement Pub/Sub with jQuery can be found at https://gist.github.com/1321768 and I'm also happy to recommend the Pub/Sub solution in AppendTo's AmplifyJS (http://amplifyjs.com/). Finally, simple Mediator pattern implementations can be found here: https://gist.github.com/1794823.