When there are new items in my inbox, I receive a an email. That mail includes [email protected] not only as the From header of that mail (“sender”), but as the To header (“recipient”) as well. So although that message was sent specifically to a single address, the header doesn't say so.

On the receiving side, this makes the message look like some kind of list message, which will get treated different from a personal message explicitely addressed to me.

Note that there is an unsubscribe link which contains the numeric ID of my user profile, 1580982 in my case. So the message is personalized. Also notice that according to comments below, including the recipient does work for bounty expiry warnings.

I wonder whether there is a good reason for the current behaviour. If not, I might turn this request for into a instead, asking the real recipient address to be named in that mail.

Please ensure that messages specifically sent to a single person will include that person't email address in the To header field of the message. Including the (user-)name as well would be an added bonus.

  • will get treated different from a personal message explicitely addressed to me -- in what way?
    – JimmyPena
    Jul 23, 2012 at 12:19
  • 2
    @JimmyPena, in my case filtered to a different folder.
    – MvG
    Jul 23, 2012 at 12:26
  • @Arjan, there is an unsubscribe link which contains the numeric ID of my user profile, 1580982 in my case. So it is personalized.
    – MvG
    Jul 23, 2012 at 12:32
  • As an aside: bounty expiration messages are sent to the correct TO address, but only include the email address, not the name. Not very important, but I'd use John <[email protected], though that needs some magic for special characters. (For which many libraries exist.)
    – Arjan
    Jul 23, 2012 at 12:40

2 Answers 2


One simple fix would be this: in the code which actually sends the message, check whether the list of recipient addresses has exactly one member. If so, change the content of the To field to be that address.

I don't know the SO codebase, but I suppose this should be a very local fix, only affecting a single function somewhere. The fact that other bulk-like mails might get personally addressed by this seems more like a feature than a bug to me. Including the name probably won't be possible with this approach, though.


One obvious reason is so that SO can send a single email to multiple recipients on the BCC line without exposing those addresses to any recipients.

The alternative is to send one email per recipient, which, while from the point of view of the wider internet is exactly the same, it's far more efficient if you relay your mail to a third party SMTP server to BCC everybody since you are then only sending a single email and your own resource usage is minimised.


As per @MvG's comment, I'd also go so far as to expect that the same code would be used for individual emails as well as for bulk emails. The only difference being how many entries are in the recipient list (that's how I'd do it anyway), therefore, I'd also expect individual emails to be sent from and to do-not-reply, with you in the BCC.

  • 1
    I very much hope that SE doesn't send notifications about my personal inbox to anyone else but me!
    – MvG
    Jul 23, 2012 at 12:25
  • D'Oh! You're right - updating my answer.
    – RivieraKid
    Jul 23, 2012 at 12:26
  • that's how I'd do it — why wouldn't you write code that allows you to set both TO and BCC...? You might be right this is the cause, but it's hardly something I'd expect. (By the way: bounty expiration warnings are sent with a correct TO address.)
    – Arjan
    Jul 23, 2012 at 12:38
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    @Arjan - because I'm lazy, and I like to write as little code as possible. Plus, if I wrote the mass-mailing code first, and it happened to work with one recipient too, there's a good chance I'd leave it at that and move on to something more important. I'm not saying it's right, or that is should be this way - I'm just saying that sometimes good enough is, well, good enough; after all, the code clearly works.
    – RivieraKid
    Jul 23, 2012 at 12:53

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