Yes, VisitorVille (
http://www.visitorville.com/ ) is for windows only machines because, although your website may be hosted remotely by some other server/host and the code is very simple to apply to the site, the actual program that allows you to view your stats in the animated 3D format from your computer is compiled in .exe (executable) format. Executable programs can typically only be read by Windows operating systems and Mac systems that have a Windows emulator running on them.
This is unfortunate because we also publish children's ebooks that are also incredibly unique at
http://www.Ebooks4Tots.com. But... they are also compiled in exe. Developers have been trying to rewrite their code to be compatible, but Mac keeps changing their configuations and processors (now using Intel) and until they settle on which way their going, PC software developers can only move on to try and improve their PC customer base.