it can be useful to put in the "world" file even the packages installed to satisfy dependencies. for example apsfilter needs imagemagick. if I don't have it in my system, emerge apsfilter will trigger the compilation of imagemagick, but it is not inserted in the world file. IMHO this is not correct. the next emerge --update world should update even imagemagic, not only apsfilter... bye
That is not the intent of the world file. Use 'emerge -u --deep world' Docs are forthcoming.