I think that in terms of moderating cotmnems its essential to have some kind of
anti-spam thing or a block (our class page has started getting individual cotmnems from
India that are adds) but I absolutely agree that a barrier to cotmnems is some of the
profile selections.  As a blogger user the settings are simple and one setting needs to
be changed to sort it out so it should take a matter of a minute.   Worse barrier
to commenting that I have would be Moodle!