The gentoo handbook for amd64 says that one should scribble something sensible in /etc/hostname and /etc/dnsdomainname. However, if one does that, the next time the system boots up, one can see a message telling that /etc/conf.d/hostname and /etc/conf.d/domainname are the places where such information should be placed.
The relevant handbook url is <URL: http://www.gentoo.org/doc/en/handbook/handbook-amd64.xml?part=1&chap=8#doc_chap2>
Steps to Reproduce:
the docs cover stable, not unstable baselayout
Closing this bug as per Josh's request in gentoo-doc's ML.