Lighttpd = Security, speed, compliance, and flexibility.
It is pronounced as “Lighty”. Lighttpd is rapidly redefining efficiency of a webserver . It is Designed and optimized for high performance environments. With a small memory footprint compared to other webservers. 128mb ram can run it like a mig29 with several wordpress(I will try two today). It has advanced feature set like FastCGI, SCGI, Auth, Output-Compression,URL Rewriting and many more. It is perfect for every server and also for VPSs with low memory. You will be amazed by its speed with low ram and swap. It is totally free.