gnash and adobe-flash: /opt/netscape/plugins/ lightspark: /usr/lib/lightspark/plugins/ vlc: /usr/lib/nsbrowser/plugins moonlight: /usr/lib64/moon/plugin/ ls -l totale 124 lrwxrwxrwx 1 root root 56 14 apr 19.56 javaplugin.so -> /usr/share/java-config-2/nsplugin/icedtea6-javaplugin.so* lrwxrwxrwx 1 root root 39 19 giu 10.33 libflashplayer.so -> /opt/netscape/plugins/libflashplayer.so* lrwxrwxrwx 1 root root 39 3 lug 13.52 libgnashplugin.so -> /opt/netscape/plugins/libgnashplugin.so* lrwxrwxrwx 1 root root 50 3 lug 14.01 liblightsparkplugin.so -> /usr/lib/lightspark/plugins/liblightsparkplugin.so* lrwxrwxrwx 1 root root 39 4 dic 2009 libmoonloader.so -> /usr/lib64/moon/plugin/libmoonloader.so* -rwxr-xr-x 1 root root 1326 25 giu 19.11 libvlcplugin.la* -rwxr-xr-x 1 root root 119520 25 giu 19.11 libvlcplugin.so* root@blight plugins # pwd /usr/lib/nsbrowser/plugins expecially the first /opt/netscape/plugins/ is so outdated as netscape was removed ages ago, plus, gnash, compiled from GPL sources, should not go to /opt. i also don't like ebuilds like vlc to put la libs there. in my opinion it would be cleaner each app to have a /usr/lib/<app>/nsplugins directory and /usr/lib/nsbrowser/plugins contain symlinks.
You will probably need to contact the maintainers of those packages individually and convince them. If this problem is very wide-spread, you might want to start an RFC on gentoo-dev. In any case, this bug is INVALID for now.