With a small memory footprint compared to other web-servers, effective management of the cpu-load, and advanced features (FastCGI, SCGI, Output-Compression, URL-Rewriting and many more) lighttpd is the perfect solution for servers suffering load problems.
thttpd is a simple, small, portable, fast, and secure HTTP server.
Simple:
It handles only the minimum necessary to implement HTTP/1.1. Well, maybe a little more than the minimum.
Small:
See the comparison chart. It also has a very small ru