The webring concept is about linking together websites of similar contents to "rings". Ringlink is a CGI Perl program for building and running such rings, and the Ringlink approach to the webring concept is made up of the Ringlink Program and the Ringlink Project.
A perl script to create a webring without the need to go through one of those annoying free webring services that put ads on your webring pages and have other annoying policies. Since the script is hosted on your server you have complete control.