You can see the video of this talk here: http://www.youtube.com/watch?v=PuNh2kp8Zt8 Our early attempts at doing client side rendering in tuenti.com brought us many performance problems, not only for the usual offenders (IE6 and IE7) but also for fast browsers like Chrome. We tried to solve most of those using a technology to render client side that ended up being faster on IE7 than Chrome, but still, things were not working. We had to scrape most of our homegrown framework and start from the beginning. We realized that the first thing we needed to do to use Javascript successfully in our thick client was to have a Javascript dependency management system. YUI came to our rescue. We also learned that in our case we would not be able to work only with client-side rendering, having server-side rendering was a must. That brings the problem of what template engine to use and whether to render server side with PHP or rather use Javascript and node so you can truly share templates between server and client. We will talk about the mistakes we made early on so you can learn from those, but also about technologies and methodologies that have (and have not) worked for us.