What is Linux?
Linux is a free operative system that has become more and more popular due to the fact that it's image is being polished from an operative system for freaks and hackers to an operating system that is graphical oriented and a possible contender to Microsoft Windows. Linux was developed by Linux Torvalds with some other programmers. It now has a huge community from all over the world working on the further development of Linux. Since Linux is free it can be obtained by any body without the need for a License, this is called the General Public License (GLP). It has all the features you would expect in a modern fully-fledged Unix, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management, and TCP/IP networking.
Linux is made up of the Kernel, which is the operating system, the Xfree86 X Windows system that provides the user interface and the graphical Desktop like GNOME and KDE that gives the Windows feel. The Kernel is the heart or the core component of the Linux operating system and it is is maintained by the thousands of corporate-supported and volunteer programmers all over the world. Linux is not owned by anybody so everyone can get a copy of the Linux operating system called (source code) modify it and distribute it further.
Another big word that you come across is the distributions. A Linux distribution is a Linux kernel that is surrounded with a lot of different applications that makes the installation of the operating system easy and provides a friendly interface for anybody familiar with a computer to use. Distributions are created by individuals and companies and is usually packed with different software for networking, communication and other software that combine with the operating system so that a normal user that use it. An example of a Linux distribution is Mandrake or Redhat.
Since the Kernel is the main thing you usually end up with kernel version that is different from the distribution version. The present Kernel version is 2.6 and while Redhat distribution is up to version 9.0 at this time. A typical distribution comes with office applications, desktops, Internet browsers, FTP clients and much more. The most interesting thing is that it's all free because nobody can claim Linux and make huge profit from it.
For further information please read the article Why Linux