I don't really get it as the RFC clearly compares two different things. Web servers included in frameworks to ease the development (django/ror and others like web.py) and a web server included in a cli interpreter which is more or less the engine itself. For me there is a huge difference and mind gap I'm not ready to do. I genuinely think that php is a convenient language for a lot of things but implementing a simple class (like SimpleHTTPServer) looks more natural to me than adding a server directly inside the cli.