On Fri, Jan 06, 2012 at 07:26:51PM -0500, Robert P. J. Day wrote: > > lunching with some friends today, and got into an interesting debate > with someone who was a lawyer and someone who was a marketing person. > > we started talking about sending out email, and whether it was > technically possible to "verify" whether an e-mail was received and/or > read. The email protocol does not include any way to check if the email has been read. People have used other tricks to tell if the email has been opened. One is the "include a link and if the person clicks on it, the email has been read". Another is the "include a picture and if that picture is downloaded, the picture has been read". These depend on the recipient reading the mail in a particular kind of browser that understands links and images, or knowing to copy the link to a browser in order to get the rest of the info. For instance, I read mail in a plain-text reader (mutt), so those tricks would not work with me. Well the link might, I've been known to paste links into browsers to see what's there. Some MTA providers (like Microsoft with their Exchange) add on whole other feature sets to their MTA (such as mail receipt checking and "recall"). That has nothing to do with the actual mail protocol. I always smirk up my sleeve when I see one of those "receipt ack. required" or "recall" messages as I don't even have a way to respond to them, even if I wanted to. For reference, the SMTP (Simple Mail Transport Protocol) is defined in RFC 5321 (http://tools.ietf.org/html/rfc5321). Hmm, I didn't know they had a new RFC for that ... but there it is. bjb