This package is missing a dependency on the set of kioslaves that will allow the program to access mail servers: "Could not start process pop3."
Anthony: it's beta, masked and never ever system critical
This is solved by emerge kde-base/kdebase-kioslaves, which provides the appropriate ioslaves. It would be helpful if there was a kdenetwork-kioslaves ebuild for this to match the others.
kmail is in kdepim. And there's kdepim-kioslaves but the pop3 slaves are provided by kdebase-kioslaves. I add it as an RDEPEND.