Nice performance pointers by web developer Kelly Norton on the problems of post page load layout (a.k.a. reflow or repaint), and how it can cause such an adverse effect on web sites and web apps.
I agree with Kelly regarding the Chrome extension Speed Tracer. Even though I feel like I’ve barely scratched the surface of what the tool can do, I’ve found it can come in handy for more complex web pages that I’m working on.