Linux is widely used on web-servers, but during 1999 the system also found many fans among more traditional PC user. Linux can to some extend replace Windows on PC's.
Linux still is difficult to install. Much hardware is not supported with drivers. And you do not find as many programs available for Linux.
Linux has many qualities: It requires less PC power than Windows do, since the design is a lot more "slim". You only install the components, you need. This gives a lot more performance from same hardware.
Linux is very stable (which you cannot claim about Windows). Linux is a NOS (Network Operating System), so it is born into the LAN.
Linux is free to use, but to get it you have to purchase an installation CD-ROM from one of the companies that distributes it.