GNOME

GNOME is a feature-rich desktop provided by the GNOME Project. It is one of the most widely-used desktops for Linux. It has been an important part of Gentoo for many years. Currently the GNOME 2 series is marked stable in Gentoo, and the GNOME 3 series is still marked as testing. Thus, "emerge gnome" on a stable system installs GNOME 2, while the same command will emerge GNOME 3 if you have "~" in your ACCEPT_KEYWORDS statement in.

Because it is so rich, "emerge gnome" requires a long time to complete. It installs a large collection of applications.

See the GNOME Configuration HOWTO for more information on installing and using GNOME.

GNOME 2
GNOME2 is a 2D desktop with 3D extensions.

GNOME 3
GNOME 3 is considered by many to be a radical departure. It needs 3D graphics capability by default, but will run in a software rendering mode if the hardware does not support 3D.

Regional Format and Localization
The display format of Dates, Times, Number, Currency and Measurement Unit can be changed according to your region via System Settings -> Region & Language -> Formats.

GUI user's guide
Gnome3's GUI is a total upheaval for users of Gnome2. Getting familiar with it, at leat for its basics, is a matter of minutes provided the user is directed to the right entry point.

A rather good entry point to quickly get familiar with this new GUI is the Gnome Help page.