Chad Perrin: SOB

29 April 2006

Reply-To Munging Considered “Big Fat Hairy Deal”

Filed under: Geek — apotheon @ 04:59

In discussion on a Perl mailing list, the subject of munging the Reply-To: headers on a mailing list came up. There’s a fair bit of disagreement on the subject.

One side of the debate consists of people who don’t want their common-case email replies to the mailing list to involve different, and more surprising, behavior than all the rest of their common-case email replies. In other words, they want to be able to use the same behavior to reply to the list as when they reply to other lists and when they reply to individual emails. They want to be able to avoid having to use group reply functionality every single time they reply to a list message, and even if they used group reply they’d like to not have to delete stuff from the recipient list to keep from sending duplicate emails to some people.

The other side of the debate mostly just keeps referring to a Web-posted document titled “Reply-To” Munging Considered Harmful, and make vague references to loss of functionality and “experts” wanting things to work the way they’re “intended” to work instead of according to some arbitrary standard.

I’m very sympathetic to the argument formula used to support the “don’t munge the Reply-To: header” side of things. It draws on all the right principles of how to handle technological functionality and usability. Unfortunately, after reading that linked document that undergirds all these arguments several times, and pondering the whole thing at great length, I find that it mostly just seems to be an empty facade. Let’s examine the arguments of the document in some detail:

The Principle of Minimal Munging The “Principle of Minimal Munging” is a good rule that will keep you out of trouble. It says you should not make any changes to an email header unless you know precisely what you want to do, why you want to do it, and what it will affect. Unless you can articulate a clear reason for munging and understand the full consequences of the action, you should not do it.

So far, so good. My question: What the hell does that have to do with it? There’s a clear benefit to munging the Reply-To: header, and its effects will be discussed shortly.

It Adds Nothing Reply-To munging does not benefit the user with a reasonable mailer. People want to munge Reply-To headers to make “reply back to the list” easy. But it already is easy. Reasonable mail programs have two separate “reply” commands: one that replies directly to the author of a message, and another that replies to the author plus all of the list recipients.

Of course this is true, as far as it goes. On the other hand, when I reply to the list, I want to reply to the list, including the originator of the message, in one swell foop. I don’t want to be spamming the poor guy’s inbox with multiple copies of the same message, nor do I want to spam any others to whom his email might have been sent via CC. I want to reply to the list and only the list. Is that so difficult to understand?

In point of fact, I use a MUA (Mail User Agent) called Mutt that has a list reply capability in addition to reply and group reply. I can use that to reply only to the list. That’s great! Bad news: I keep accidentally sending emails only to the originator, skipping the list entirely, because when I reply to emails I usually just use reply. Muscle memory and default behaviors have trained me that way, and it’s to my advantage to stay trained that way rather than training myself to try the list reply option first all the time as the default because of all the mailing lists and individual correspondents with whom I deal regularly, none but this one list fails to provide the most natural behavior as standard via the Reply-To: header.

If you use a reasonable mailer, Reply-To munging does not provide any new functionality. It, in fact, decreases functionality. Reply-To munging destroys the “reply-to-author” capability. Munging makes this command act effectively the same as the “reply-to-group” function.

Poppycock! Utter balderdash! What is this sophistry?

What actually happens with Reply-To: munging is as follows:

The Reply-To: acts exactly as it always has, in that it defaults to replying to a single recipient address, except that the recipient address is for the list instead of the author — the list of which the author is presumably a member. For most interactive mailing lists, this is the most common case for an email reply. It is also the most commonly desirable manner of handling an email reply for an interactive mailing list, because such mailing lists are designed for sharing information, and not for encouraging people to avoid using them. The ability to email the original author is now relegated to second-class citizen, rather than emailing the list being the second-class citizen: just as without munging you can normally only reply to the author or the list and the author, so now with munging you can normally only reply to the list or the author and the list. No functionality is really removed. You’ve just altered the defaults.

Anyone that thinks replying only to the list is exactly equivalent to replying to the list and the author at the same time with the same text probably hasn’t been the recipient of multiple copies enough to “get it”.

Freedom of Choice Some administrators justify Reply-To munging by saying, “All responses should go directly to the list anyway.” This is arrogant. You should allow me to decide exactly how I wish to respond to a message.

Ut-oh. We’re getting politically spurious now. The word “freedom” has been brought to the table.

The truth is, you can direct it to whoever you like just the same as you always could. You just have to edit the recipients in the less common case for a mailing list now, rather than for the most common case, to avoid a faux pas — and yes, it is a faux pas to send me two copies of every single friggin’ email. Are you afraid one of them is going to get wet in transmission and be illegible when it gets here?

Can’t Find My Way Back Home Reply-To munging can make it impossible to reach the sender of a message.

. . . unless, as you might have gathered from the above, you’re not too lazy to edit the group reply recipients.

Coddling the Brain-Dead, Penalizing the Conscientious There are, unfortunately, poorly implemented mail programs that lack separate reply-to-author and reply-to-group functions. A user saddled with such a brain-dead mailer can benefit from Reply-To munging. It makes it easier for him or her to send responses directly to the list. This change, however, penalizes the conscientious person that uses a reasonable mailer.

This is just more of the same spurious nonsense as the above. You’re punishing one group by making them type stuff so that another group doesn’t have to delete stuff — and, meanwhile, you’re punishing the second group by having to delete stuff anyway if they don’t want to be boorish jackasses that don’t care if someone’s list email traffic is doubled for no good reason. I thought all the old-school computer geeks were big on the light:heat ratio. The particular geek that created that document, along with his followers, apparently prefers heat over light — though I can’t imagine why.

Principle of Least Work

There’s a stupid table here. You can go read it yourself. The guy that created it was really reaching when he came up with this nonsense. It’s not even plausible enough to call it sophistry, unfortunately. If you really want to reply to everyone all the time, just hit the damned g key and don’t bother using the r key at all, on this munged-header mailing list. If you want to reply only to the author, you can always just use the g key and delete recipients you don’t want. Considering that with list traffic the vast majority of people will be replying to the list (only) the vast majority of the time, the work involved in the unmunged-header list is multiplied quite a bit by the number of times a day you may have to do the work, in addition to which there are more accidental missends that have to be dealt with and either a bunch of line noise in the form of duplicate emails or a bunch of extra effort involved in deleting a recipient basically every time you send a reply. The fact that the guy pretty much lied about the requirements for replies on a munged-header list to inflate the apparent effort cost is just icing on the cake after that.

Principle of Least Surprise When I hit the “r” key in Elm, it sends a response to the author of a message. When you munge the Reply-To header you change this action so that it does something entirely different from what I expect. This creates specialized behavior for your mailing list, which increases the potential for surprise. I’m not schooled in the science of human factors, but I suspect surprise is not an element of a robust user interface. Private messages frequently are broadcast across lists that do Reply-To munging. That’s an empirical fact. It’s what happens when you violate the principle of least surprise.

That may have been more commonly true in 1985, but things have changed. Munging the Reply-To: header for mailing lists is the default by now. In the last decade, I might have run across one other mailing list that didn’t munge the Reply-To: header, and in that case it was an oversight that got corrected when people complained. There are apparently three Elm users in the world who share his opinion, and the other six billion of us (including a bunch of Elm users) find that his approach is the more surprising.

Saying something is unsurprising doesn’t make it so.

Principle of Least Damage Consider the damage when things go awry. If you do not munge the Reply-To header and a list subscriber accidentally sends a response via private email instead of to the list, he or she has to follow up with a message that says, “Ooops! I meant to send that to the list. Could you please forward a copy for me.” That’s a hassle, and it happens from time to time. What happens, however, when a person mistakenly broadcasts a private message to the entire list?

This is the first genuinely relevant concern in the entire damned thing. It ignores the damage done by sucking up others’ time by making them process twice as much mail, though, and assumes a far greater incidence of accidentally list-sent private emails than seems to actually occur. I’ve seen about two such instances in a decade of mailing lists, sometimes with hundreds of emails crossing the lists every day, all the lists using a munged Reply-To: header. In one day on this unmunged-header list, there were six missent messages of which I was aware. I have no idea how many simply went unremarked.

Six. On a list that got about thirty messages that day. One in five. At a rate of, say, a hundred a day for a decade, that would be roughly 730 missent messages. Now, add to the frustration pool the fact that probably at minimum 50% of the messages would have been sent by lazy bastards like the guy that wrote that document, who don’t care about the fact that they’re halving the the light:heat efficiency of the list, and that the other 50% of messages are sent by users who then have had to go through the contortions of deleting recipients when doing a group-reply. Tell me what the comparative damage tally is now.

And in the End… If you are not convinced yet, then allow me one final plea. I contribute to the Elm mailer development team. I get to see a lot of the wants and requests from the user community. Guess what feature more and more people are asking for? A third reply command — one that ignores any existing Reply-To header!

Okay. Now tell us what it does reply to! Are you talking about list reply capability like Mutt has? I already mentioned I use Mutt, which has this functionality. My take is that it’s kind of a pain in the butt to have to remember a completely different set of behaviors for list traffic from what I use for individual emails. All it does is make the notion of a group reply less rude: I still have to remember to use it, which I don’t always do.

If this doesn’t refer to a list reply feature, I can only imagine it must be a means of replying with an empty recipient field. I could see that being useful maybe once every century, on average.

Addendum In case you are wondering, yes, I once thought Reply-To munging was a nifty idea. I got better though. When I started running email lists, I munged ’em all. One day I accidentally sent a private, personal reply out over one of my own damn lists. If the list owner can’t remember how to use the list properly, no way will the subscribers be able to sort it out. I stopped munging the very next day. On the whole, it has worked out quite well. Yes, on occasion somebody mistakenly responds directly to the author of a message when they wanted to reply to the group.

That’s asinine. You simply need to realize that you’re responding to a list message. You should be thinking about your audience and the content of your messages all the time anyway. Don’t punish me because you’re careless and had one individual bad experience. Poor thing. I’m suffering (slightly less) bad experiences on a daily basis because people actually think your arguments hold water.

I love the way you define “on occasion” as “several times a day”, and you’re so terribly concerned about the plague of public slip-ups that consiste of “several times a decade”. I think you wore your priorities backwards today.

All original content Copyright Chad Perrin: Distributed under the terms of the Open Works License