Because he said he wanted to be able to do the firefox update direct
from firefox.com as an ordinary user, and that isn't permitted for the
ubuntu package, which is updated by the package manager.

I agree that synaptic is the way to go. I use the ff-3.5 and 3.6 daily
builds, from the ubuntu repositories and don't see the point of what he
wants to do.

Nevertheless, he asked how to do it, and I told him how, but also also
gave him a pointer to a howto on keeping it updated with synaptic instead.