The best way to learn about the tools is to visit the site and try them. The reason why we came across the site is that we were trying to determine what sites were on a web server (to determine how loaded or overloaded the server is). The tool is the “Reverse IP Domain Check”. For instance, I did a search on my PCIN.net domain, and found that the IP address of my server (18.104.22.168) has 177 different sites hosted (seems excessive to me!).