Simulate Slow Internet Connection

I came across this article today that describers how you can use Firefox Throttle to reduce your internet connection speed. Here is a quote for why you should test under these conditions.

Well the truth is that real world internet connections are much slower than you think. Your application end users may not always be broadband users but also people accessing your app through a dial-up connection, mobile sets, 3G or USB dongles. Most designers and developers forget to test their application on slower internet connections, resulting in a poor performing application.

Another good addon that can help you find the bottlenecks in your code and help optimize it is Google Page Speed.This addon allows you to see how your code could be optimized and will generate the suggested changes.