That only works with packages included in the distro (yes there is allot there but that is besides the point). NVU (for example) is not there..
NVU is now called Kompozer and is in the Ubuntu repo.
knitebane@laptop:~$ apt-cache search kompozer
kompozer - Complete Web Authoring System
kompozer-dev - KompoZer development files
nvu - Transition package for Nvu --> KompoZer fork
nvu-dev - Transition package for Nvu --> KompoZer fork (development files)