On Fri, Jan 06, 2012 at 10:59:25PM -0500, Shawn H Corey wrote: > On 12-01-06 10:48 PM, Brenda J. Butler wrote: > > On Fri, Jan 06, 2012 at 10:42:47PM -0500, Brenda J. Butler wrote: > >> On Fri, Jan 06, 2012 at 10:28:34PM -0500, Shawn H Corey wrote: > >>> On 12-01-06 10:12 PM, Brenda J. Butler wrote: > >>>> 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". > >>> > >>> Won't work. I have a filter on my email that checks to see if you're on > >>> my black list, and if so, sends it directly to trash and marks it read. > >>> I never see it. > >> > >> This "marks it read" feature is for you to know which emails you have > >> read. It is not for the sender to know whether you have read their > >> message. That is a separate feature, implemented differently. > > > > More explicitly: > > > > The "emails I've read" information is kept locally on your machine, > > about which emails that you've already received have been read > > by you. It is not part of the email exchange protocol at all. > > If my machine marks it as read and sends back a receipt saying so, the > sender will think I have read it when in fact, I have not. There is no > way to guarantee a person has read the mail. The only thing you can tell > is that somewhere along the line a machine has marked it as read. The > only way to guarantee that the mail has reached the recipient's machine > is to search that machine for it. Email is *not* guaranteed. You cannot guarantee that a registered letter has been *read* by the intended recipient either. It is guaranteed to have been *received* by *someone who signed for it* at the destination though. For a machine, that isn't saying much. > Shawn slainte mhath, RGB -- Richard Guy Briggs -- ~\ -- ~\ <hpv.tricolour.net> <www.TriColour.net> -- \___ o \@ @ Ride yer bike! Ottawa, ON, CANADA -- Lo_>__M__\\/\%__\\/\% Vote! -- <greenparty.ca>_____GTVS6#790__(*)__(*)________(*)(*)_________________