freebsd news group definitions, newbie

[toby]

I do not understand what some of the prefixs mean for the freebsd news
groups. For example:

list
mailing
anarch
comp
mpc
muc

I do not know if I should post to some of these groups or not. The rest of
the group definition is self explaining, it is the prefixs that confuse me.
I seems that many of the news groups are duplicated with different prefixs.
Can anybody explain this to a newbie?

Thanks