Check this out from Gentoo.org
Gentoo Linux in a paragraph
We produce Gentoo Linux, a special flavor of Linux that can be automatically optimized and customized for just about any application or need. Extreme performance, configurability and a top-notch user and developer community are all hallmarks of the Gentoo experience.
Thanks to a technology called Portage, Gentoo Linux can become an ideal secure server, development workstation, professional desktop, gaming system, embedded solution or something else -- whatever you need it to be. Because of its near-unlimited adaptability, we call Gentoo Linux a metadistribution.
What is Portage?
Portage is the heart of Gentoo Linux, and performs many key functions. For one, Portage is the software distribution system for Gentoo Linux. To get the latest software for Gentoo Linux, you type one command: emerge sync. This command tells Portage to update your local "Portage tree" over the Internet. Your local Portage tree contains a complete collection of scripts that can be used by Portage to create and install the latest Gentoo packages. Currently, we have nearly 6000 packages in our Portage tree, with new ones being added all the time.
Portage is also a package building and installation system. When you want to install a package, you type emerge packagename, at which point Portage automatically builds a custom version of the package to your exact specifications, optimizing it for your hardware and ensuring that the optional features in the package that you want are enabled -- and those you don't want aren't.
Portage also keeps your system up-to-date. Typing emerge -u world -- one command -- will ensure that all the packages that you want on your system are updated automatically.
Gentoo Linux 2004.1
Portage will keep your Gentoo Linux system as "up-to-date" as you desire. And because of this, experienced Gentoo users don't pay too much attention to "new versions" of Gentoo Linux -- after all, the latest and greatest version of Gentoo Linux is always available by typing an emerge sync command. There's no need to wait several months for a "new version" of Gentoo Linux to be released because Gentoo Linux is continually updated and refined and these improvements are immediately made available to you.
Of course, we do roll up official CD releases of Gentoo Linux so that new Gentoo Linux installs are as up-to-date as possible from the start. Here's an overview of what is included in the recent 2004.1 release of Gentoo Linux:
Support for x86, AMD64, PowerPC, UltraSparc, Alpha and MIPS processors
LiveCD-based installation for x86, AMD64, PowerPC, UltraSparc and Alpha
Latest stable KDE and GNOME
Various optimized Linux kernels
Very modern GNU development environment
Excellent filesystem support: ReiserFS, XFS, ext3, EVMS, LVM
Excellent hardware support: NVIDIA, Creative Labs Live! and Audigy
Modular OpenGL and compiler sub-system (supports multiple co-existing versions)
Clean, dependency-based system initialization scripts
New "hardened" Gentoo security initiative
6000+ packages of the latest and greatest software
Enhanced Portage capabilities
If the power, speed and flexibility of Gentoo Linux appeals to you, then we encourage you to give it a try. "