Now, mod_fastcgi is configured and running. FastCGI supports connection via UNIX sockets or TCP/IP networking. This is useful to spread load among various backends. For example, php will be severed from 192.168.1.10 and python / ruby on rails will be severed from 192.168.1.11. This is only possible with mod_fastcgi.
Lighttpd allows you to run php from different hosts. This is quite useful: a] If you want to run php 4 locally and php 5 from remote host b] Load balancing dynamic content c] Added layer for security for chrooted jails etc If you would like to run wikipedia / sf.net like site, you can [...]
FastCGI is a language independent, scalable, open extension to CGI that provides high performance without the limitations of server specific APIs. FastCGI provides better scalability and performance. Instead of creating a new process (the CGI program) for every request, FastCGI uses a single persistent process which handles many requests over its lifetime. (See wikipedia article [...]