Arch Linux is an independently developed, i686/x86-64 general purpose GNU/Linux distribution versatile enough to suit any role. Development focuses on simplicity, minimalism, and code elegance. Arch is installed as a minimal base system, configured by the user upon which their own ideal environment is assembled by installing only what is required or desired for their unique purposes. GUI configuration utilities are not officially provided, and most system configuration is performed from the shell by editing simple text files. Arch strives to stay bleeding edge, and typically offers the latest stable versions of most software.
Arch Linux uses its own Pacman package manager, which couples simple binary packages with an easy-to-use package build system. This allows users to easily manage and customize packages ranging from official Arch software to the users own personal packages to packages from 3rd party sources. The repository system also allows users to easily build and maintain their own custom build scripts, packages, and repositories, encouraging community growth and contribution.
The minimal Arch base package set resides in the streamlined core repository. In addition, the official extra, community, and testing repositories provide several thousand high-quality, packages to meet your software demands. Arch also offers an unsupported section in the Arch Linux User Repository (AUR), which contains over 9,000 build scripts, for compiling installable packages from source using the Arch Linux makepkg application.
Arch Linux uses a "rolling release" system which allows one-time installation and perpetual software upgrades. It is not generally necessary to reinstall or upgrade your Arch Linux system from one "version" to the next. By issuing one command, an Arch system is kept up-to-date and on the bleeding edge.
Arch strives to keep its packages as close to the original upstream software as possible. Patches are applied only when necessary to ensure an application compiles and runs correctly with the other packages installed on an up-to-date Arch system.
To summarize: Arch Linux is a versatile, and simple distribution designed to fit the needs of the competent Linux user. It is both powerful and easy to manage, making it an ideal distro for servers and workstations. Take it in any direction you like. If you share this vision of what a GNU/Linux distribution should be, then you are welcomed and encouraged to use it freely, get involved, and contribute to the community. Welcome to Arch!