The ebuild does not specify emul-linux-x86-sound as a dependency for this version of Skype which introduces ALSA support. Hence, the application will not start, missing the x86 version of libasound.so.2.
There's no skype-1-3-0-30-r1 in portage. And skype-1.3.0.37 already depends on emul-linux-x86-soundlibs.