Load Impact - Free web site load test
http://loadimpact.com/

Utilidad online para probar la carga de un website, hace un test para probar la respuesta del site por encima de 40 clientes conectados

testt website - cool tool

Slow websites means lost customers and revenues. Be proactive and find out the performance limits of your website before you learn it the hard way. Load Impact is an online load testing service that lets you load test your web site with just a few mouse clicks.

Load Data while Scrolling Page Down with jQuery and PHP

Like scroll in google reader

"Even Faster Web Sites"

Not too long ago, I wrote about loading JavaScript without blocking by creating a dynamic <script> tag. When <script> tags are in the flow of an HTML document, the browser must stop rendering and wait for the script file to download and execute before continuing (example). Creating a new <script> tag via JavaScript avoids this issue because it’s out of the flow of the document, so the script file is downloaded and executed without waiting. The result: dynamically loading JavaScript files allows your page to render faster and therefore improve perceived performance.

handling dependancies in js

Lazy Load Image lazy loader plugin for jQuery.

Delays Loading of Images with Lazy Loader jQuery Plugin

Configuring nginx as load balancer

Nginx