Joseph Smarr is the Chief Platform Architect at Plaxo, Inc., where he’s led the engineering of Plaxo’s address-book integration application. In the course of building Plaxo 3.0, which involved an ambitious foray into rich internet application design, Joseph and learned a host of lessons about the importance of performance and the means by which it can be achieved. Many of those lessons (“premature optimization is the root of all evil”) will be familiar. But some run contrary to what are commonly thought of as best practice in frontend engineering. In this talk, Smarr explores the core lessons that he and his Plaxo team have learned and the details of how they leveraged maximum performance from the web browser in the creation of Plaxo 3.0.