I have used thttpd as my web server of choice for a very long time. In fact, I have even contributed a few patches to it. I like it because it is a fast, lightweight, portable server. However, it has not been under active development for a very long time, and operating systems now have better mechanisms for serving data to clients. Hence, according to my very informal tests, lighttpd is faster that thttpd (approximately 5 - 15% faster on my Linux system). Even better, lighttpd has more features. It supports SSL, transparent compression, PHP, FastCGI, URL redirection, and more. It also has a plugin API so you can write code that interfaces with it directly. It isn't as fully featured as Apache, but it is much faster (at least for static content). In basically every way, it seems to be superior to thttpd.