[Mailman-Users] how to get "my letter is opened" information without Delivery or read receipts are being checked

[Barry S, Finkel]

On 4/16/2012 7:26 AM, Bernd Petrovitsch wrote:
> Generally, don't do it because just someone "opened" the mail, it
> doesn't imply that s/he read it. And reading it doesn't imply the s/he
> understands it.
IIRC, the mail RFCs state that the header line:

      Return-Receipt Requested:

is not standardized in its implementation.  The return receipt might be
sent

      when the mail is placed in the recipient's mailbox, or
      when the recipient opens the mail, or
      the recipient's Mail User Agent might ignore the line.

Thus, there is no way to know for sure that the recipient has read
the mail except, of course, to request that the recipient send a
reply.
--Barry Finkel