$ equery u gconf ldap : Adds LDAP support (Lightweight Directory Access Protocol) policykit : Enable PolicyKit authentication support The default descriptions for the `ldap' and `policykit' USE flags don't really let you know what they're actually supposed to do, and thusly, aren't very useful. To my understanding, GConf's `policykit' integration exposes an extra dbus interface for changing system-wide defaults, using sys-auth/polkit for authentication. And `ldap' seems to enable an extra backend that pulls email addresses, contacts and similar data from an LDAP server, and stuffs them into keys in `/apps/evolution/*'.
I don't think it's worth spending time on it since it is getting deprecated.
I don't think it needs a specific description for "policykit", it has a similar behavior as in other packages. About "ldap", it's different and that information can be taken from a readme file in sources tarball :-/
+ 12 Mar 2011; Pacho Ramos <pacho@gentoo.org> metadata.xml: + Improve 'ldap' USE description (bug #352358 by Dean Matzkov). +