Steam is a content delivery system for linux gaming.
install part 1
funtoo & gentoo have ebuilds in the gamerlay overlay. the steam-meta ebuild was removed.
root # layman -a gamerlay root # layman -S root # emerge steam-launcher
install part 2
steam has its own internal package management system. Portage will not track its files, or games installed. the ebuild simply pulls in the steam installer, to run the steam installer:
root # /usr/bin/steam
the installer will prompt you with several questions, once done running the installer command will load the latest version of steam.