For the development/testing of any client-server app where you anticipate deployment to a network with variable latency. In 2010 this means websites. Mostly to

For the development/testing of any client-server app where you anticipate deployment to a network with variable latency. In 2010 this means websites. Mostly to simulate the real-world UX of ajax sites that have a lot of server roundtrips. It's vital in these kind of interfaces for everything to happen before the magic 150ms threshold of perceived instantaneousness.