Social Networks and Collaborative Groupware Software: CL-HTTP Common Lisp HTTP Server

Collaborative Groupware Software
Ben links to a discussion on social netoworks. The list of Collaborative Groupware Software is extensive and includes Open Source as well as commercial options. Potentially the most interesting link is CL-HTTP:

CL-HTTP is a full-featured server for the Internet Hypertext Transfer Protocol (HTTP 1.1, HTML 2.0, HTML 3.2 & pre-HTML 4.0) that comes complete with source code. The server has been proven in major production systems and applied in a number of Artificial Intelligence systems.

I was trying to find this project a year ago after listening to Paul Graham discuss a new programming language he had been working on for 2 weeks.
Arc: A New Dialect of Lisp you can listen to the presentation online or download the mp3 file.

I could not track it down at the time. For those who don't know, Paul wrote an ecommerce "Shopping Site" code in Lisp. It was a very successful project and after he sold the company to Yahoo they renamed it "Yahoo Shops".