The slides for this presentation can be found over on SpeakerDeck. I'm also happy to recommend Michael Mahemoff's 'Web-First Design Patterns' slides for follow-up reading and of course, Nicholas Zakas's 'Scalable Application Architecture' talk.
Video 1/3: Architecture For Small-Medium Size Apps (23 mins)
Video 2/3: Writing Modular Code (16 mins)
Video 3/3: Patterns For Large-Scale Development (33 mins)
It's important to stress that there are many ways of building large-scale applications. The approaches mentioned are but one that have worked for a number of large sites. Developers have also successfully crafted non-trivial solutions using everything from Dojo to Backbone.js, so do make sure to research your options before committing to any patterns or frameworks.