CGI is to HTTP what VNFS is to NFS, SMB or AppleShare!
With HTTP, a WWW browser (such as Netscape or Internet Explorer) on the client machine sends requests across a network to a server running a HTTP daemon which sends back a reply.
With a network file protocol (such as Sun’s NFS, Microsoft’s SMB or AppleShare) similar request and reply packets are sent across a network.
CGI and htbin on the server allow the reply to be computed on-the-fly rather than stored on disk.