Windows hosting means hosting of web services that runs on the Windows operating system.
You should choose Windows hosting if you plan to use ASP (Active Server Pages) as server scripting, or if you plan to use a database like Microsoft Access or Microsoft SQL Server. Windows hosting is also the best choice if you plan to develop your web site using Microsoft Front Page.
Unix HostingUnix hosting means hosting of web services that runs on the Unix operating system.
Unix was the first (original) web server operating system, and it is known for being reliable and stable. Often less expensive than Windows.
Linux HostingLinux hosting means hosting of web services that runs on the Linux operating system.
CGICGI scripts are executables that will execute on the server to produce dynamic and interactive web pages.
Most ISPs offer some kind of CGI capabilities. ISPs often offer preinstalled, ready to run, guest-books, page-counters, and chat-forums solutions in CGI.
CGI is most common on Unix or Linux servers.