Reply-to-List, or Reply-to-All?
There is an open question about the best "netiquette" to use when replying
to mailing list messages — should you use "Reply to All" and include
the original sender of the message and all other recipients well as the list,
or should you use "Reply to List" and send your message only to the
Note that this is not the same topic as discussed in Chip Rosenthal's
Considerered Harmful" essay. That essay is about what the list
should do, while this page talks about your choices as the user who
is replying to the mail.
Different people have different preferences, use different software, and
have different ways of processing their incoming mail. For example:
Each of these people may have different preferences — it's hard
to know what to do for the best, and whether to include them in Cc
or not when you reply to their messages.
- Fred filters all incoming messages into separate folders according
to the list it comes from. If you send a message which is cross-posted
to two lists that he's subscribed to, and Cc him directly because you
know he has a personal interest and you don't know that he's subscribed
(or suspect he might not be looking in those folders very often), then
he will have separate copies in each list folder, in addition to the
copy in his INBOX.
- John doesn't do any filtering — he isn't subscribed to many
mailing lists, so hasn't bothered to work out how to do it. If you
Cc him on a message which is also sent to a list he's on,
then he'll see two copies of that message in his INBOX.
- Mary has configured her mail software so that it automatically
filters out "duplicates", depending on a Message-Id:
header which is supposed to be unique in all email
messages. So she'll only ever see one copy of the message,
usually the one which arrives first.
(If she's included directly in Cc then the direct copy
is fairly sure to be the first to arrive, so she'll only get the
copy in her INBOX. If she's not in Cc and the message is sent
to more than one mailing list that she's on, then she'll only see the
copy which arrives from whichever mailing list is fastest. If she
filters list mail into folders, it's basically random which
list folder it goes into.)
- Claire is not subscribed to the list at all. She's been added to
Cc because she has an interest in this particular
discussion, and can offer expert advice even though she's not
usually involved with this project at all.
- Karl is not subscribed to the same list as you; he's subscribed to
a different mailing list. If you are participating in a discussion
which crosses project boundaries and is cross-posted to more than
one list, he will only see messages which are posted to
the list he's subscribed to.
Obviously if they have told you their preference, then that's not
so hard — just do as they ask. But most of the time you don't know;
you have to guess. And when we're working on mail software, we have to set
the default behaviour for a non-private reply. That's what prompted me to
write this page.
Pros and Cons
Let's look at what goes wrong if you make the wrong choices...
If you choose 'Reply to All', then everybody will get a copy. That may
annoy John and Mary a little bit, because...
If you choose 'Reply to List', then your reply will go just to
one address; a mailing list address. In the case of
cross-posted messages, which list that is will depend on which copy of
the message you reply to. If you're like Mary and you filter
"duplicates", that basically means that you'll continue the discussion
on whatever list has the fastest mailing list software.
So what happens is...
- John will receive two copies of the mail in his INBOX.
- Mary will receive the mail in her INBOX and not in the list folder.
- Claire is dropped from the discussion completely, because you
dropped her from Cc.
- Karl is dropped from the discussion completely, along with everyone
else on that mailing list.
- John and Mary are happy.
- Fred may or may not see the discussion; depending on how often he
looks into the folder for the list you happened to reply to.
- Because list software can often be slow, the active participants
may experience a long delay before seeing your response —
so by the time they have the chance to reply, the discussion may
have moved on and they may have missed their chance.
You may not have spent too much time thinking about the different ways
that people handle email; hopefully the above has given you some pointers.
Now it's time for you to make your own decision — if you don't know
what the sender prefers, which one do you guess?
The corollary to the same question is: If you're working on a mail program,
what should you make the default behaviour, if the user doesn't
express a preference?
I've tried to stick to the facts so far and not offer my opinion. If
you don't want to know what I think, you can look away now...
To me, the answer seems obvious when you look at the failure modes:
Yes, it's true that in Mary's case if you "Reply to All" then she might
miss the copy of the mail in her list folder, as it'll arrive in her
INBOX instead. But it's a fairly safe bet that she'll see it there
anyway, and she can always move it to the list folder if she wants
to. It's still not much of an issue; at least she has it.
- If you "Reply to All" then some people may get a second copy of the
message... not really the end of the world.
- If you "Reply to List" then some people could be cut out of the
discussion completely, and for a cross-posted discussion
you risk splitting the thread into separate discussions on
Besides, Mary ought to be used to messages not being in the right
list folder anyway. As described above, her setup means that if a
message is sent to more than one mailing list that she's subscribed
to, she'll get only one copy of that message — in an
essentially random choice of list folders depending on which list is
faster. That was her choice.
(There's a strong argument that Mary's mail setup is
broken, because you can't really depend on the
Message-Id: header being unique. For fun, try sending
messages to various people "including" Mary, but make the
Message-Id: the same on all of your messages. Mary will only
see the first, and you can say what you like about her after that,
while other people think she's in Cc. You can also prevent
her from receiving list messages you don't want her to see, if you
were included directly in Cc so you get them before she
does. You just need to quickly send her a different message with the
same Message-Id: as the message you want her to miss —
as long as yours gets there first, her mail software will helpfully
delete the message you didn't want her to see.)
So really, the decision is a no-brainer. Unless you know that
the other people involved in the discussion are like Mary or John,
then you should always play it safe and use "Reply to All".
Deliberately replying only to the list and cutting others out of the
discussion is considered to be extremely rude by some people.
Public vs. Private replies
So far, I've only spoken about the case where you know you want to
reply in public. When we're thinking about what mail software should do,
and what the default behaviour should be, we also have to consider the
question of "public or private?".
This one takes even less thought, and again the decision can be
based entirely on the failure modes:
So although people have occasionally asked for the default 'Reply' button and
the associated 'Reply to Sender' menu option to actually
reply to the list for list messages, that seems like a really bad idea
— and most of the time they realise this when it's pointed out to them.
- If you send a private reply when the user expected it to be public,
that is easy to fix — just forward or resend the message to
the correct place.
- If you send a public reply when the user expected it to be private,
the effects of that can be catastrophic — the public
message can never be retracted, and could be extremely damaging.
Any decent mail program will have separate options for a
private reply, vs. a more public reply — and the private reply option
should never trick you into replying back to the list.
For mailing list administrators, this is probably a reasonable time to refer back to the Reply-To-Harmful
essay that I mentioned in the second paragraph. Setting a Reply-To:
address to point back to the list is doing the wrong thing in
both ways. It's hijacking my private "Reply" button and
making it give a public reply, when I already had a button
that I could use if I wanted to make a public reply. And it's even giving the
wrong type of public reply — it's replying only to the list,
instead of to all the correspondents.
Please, never set a mailing list to have a Reply-To: header
point back to the list. That's like sending me a virus which infects my mail
program and hacks it so that it replies in public when I specifically pressed
the button which should give me a private reply. If I wanted to send
a public reply, the button for that is right next to the one I pressed!
If I'd wanted that, I would have pressed it.
Thankfully, I now have this to save me:
This is what we currently have in Evolution: a private Reply button, and
a 'Group Reply' button which gives you a dropdown choice of Reply-to-All vs.
You don't have to use the drop-down menu, of course — if you
just click 'Group Reply', it'll do the sane default which is Reply-to-All.
You can go into the preferences and change the default to be
Reply-to-List. Please don't, though.