Paul Jakma napisał(a):

> The person you are replying to can/may:
> 
> - /want/ the direct copy (this is the case for quite a few people on
>   this list)

I prefere, and I do it, explicit asking for a CC.

> - filter incoming mail to supress duplicates

It is a lot easier to find personal mails than to suppress dupes.
In the former case you can look at References or IRT fields and in the
later you have to *keep* a list of Message-IDs and search it everytime
you receive a letter.

And direct replying generates more traffic.

I started this thread because I never liked to receive personal
duplicates of mails sent to lists. That is why I decided to ask you for
your opinion.

EOT
-- 
Było mi bardzo miło.                    Trzecia pospolita klęska, [...]
>Łukasz<                      Już nie katolicka lecz złodziejska.  (c)PP