"The goal of Varnish is to be a very fast, stable and effective light-weight HTTP accelerator daemon, by using modern and effective technologies.

[...] When we set out to design and implement a high-performance HTTP accelerator about a year ago, we knew that we could improve on the state of the art, but we did not quite realize how much room for improvement there was. A year later, we have an HTTP accelerator that can run at wire speed on cheap off-the-shelf hardware. The difference in performance between Varnish and our closest open source competitor is almost two orders of magnitude."