Thanks for the compliment! I'm glad that you liked the site! :D
I am still learning about Backbone.js as well, there are so many things that you can do with it that I haven't really utilize all the features yet. If you need any help with it, feel free to buzz me!
So far, the only thing that we use Flash for is for Websockets transport (if your browser doesn't support Websockets, it falls back to use Flashsockets... Socket.IO FTW), and the Youtube videos embedding.
The Youtube Javascript API for embedding videos automatically chooses the best method of embedding videos in your browser based on your system and machine. If you have opted-in to use the HTML5 version of Youtube embeds, you should get HTML5 of Youtube embeds on every site you go. :) To do that, you have to go here: http://www.youtube.com/html5
Everything else is done with HTML, CSS and Javascript though. I hope you're good with HTML5 and CSS3! We are strong supporters of HTML5, so we try not to use flash whenever we can. :D
We'll be adding more OAuth methods in the future, such as Twitter and Google. Thanks for the suggestion!
Hi, I'm the frontend developer for the site. As the site is very heavy with interactions, we decided to use Backbone.js to keep things organized and jQuery for updating states, ajax calls, keeping the DOM updated throughout etc. We use Socket.IO as the data transport between server and client.
For animations, we use CSS3 animations as much as possible for the non-essential elements to make use of hardware accelerated animations. However the video fade-in and fade-out effect is done using jQuery though... I haven't figure out an easy way to do that with CSS3 yet and keep it consistant across browsers, it's tough to keep the timing right, lol.
Personally I think Backbone.JS and jQuery are a match made in heaven. In fact Backbone.js is built with jQuery or Sizzle in mind. The latest Backbone.js supports caching of view elements as well (with the "this.$el") and event delegation with $.fn.on and $.fn.off, keeping the frontend fast and efficient. :)