Gnome Desktop Environment

GNOME is a desktop environment—a graphical user interface which runs on top of a computer operating system—composed entirely of free and open source software. It is an international project that includes creating software development frameworks, selecting application software for the desktop, and working on the programs which manage application launching, file handling, and window and task management.

GNOME is part of the GNU Project and can be used with various Unix-like operating systems, most notably those built on top of the Linux kernel and the GNU userland, and as part of Java Desktop System in Solaris.

According to the GNOME website:

The GNOME project provides two things: The GNOME desktop environment, an intuitive and attractive desktop for users, and the GNOME development platform, an extensive framework for building applications that integrate into the rest of the desktop.

The GNOME project puts heavy emphasis on simplicity, usability, and making things “just work”. The other aims of the project are:

• Freedom—to create a desktop environment that will always have the source code available for re-use under a free software license.
• Accessibility—ensuring the desktop can be used by anyone, regardless of technical skill or physical disability.
• Internationalization and localization—making the desktop available in many languages. At the moment GNOME is being translated to 166 languages.
• Developer-friendliness—ensuring it is easy to write software that integrates smoothly with the desktop, and allow developers a free choice of programming language.
• Organization—a regular release cycle and a disciplined community structure.
• Support—ensuring backing from other institutions beyond the GNOME community.

Origins

In 1996, the KDE project was started. KDE was free and open source from the start, but members of the GNU project were concerned with KDE's dependence on the then non-GPL Qt widget toolkit. In August 1997, two projects were started in response to this issue: the Harmony toolkit (a free replacement for the Qt libraries) and GNOME (a different desktop not using Qt, but built entirely on top of GPL and LGPL licensed software). The initial project leaders for GNOME were Miguel de Icaza and Federico Mena.

In place of the Qt toolkit, GTK+ was chosen as the base of the GNOME desktop. GTK+ uses the GNU Lesser General Public License (LGPL), a free software license that allows GPL-incompatible software (including proprietary software) to link to it. The GNOME desktop itself is licensed under the LGPL for its libraries, and the GPL for applications that are part of the GNOME project. Having the toolkit and libraries under the LGPL allowed applications written for GNOME to use a much wider set of licenses (including proprietary software licenses).

In 1998, Qt became GPL. While Qt was dual-licensed under both the QPL and the GPL, the freedom to link proprietary software with GTK+ at no charge made it differ from Qt. With Qt licensed under the GPL, the Harmony Project stopped its efforts at the end of 2000, as KDE did not depend on non-GPL software anymore. In contrast, as of 2009, the development of GNOME has not stopped.

In March 2009, Qt 4.5 was released, adding another licensing option, the LGPL.

More info about Gnome here