I'm not actually sure they did much better than a regular image for tracking opens though I believe they also did a background-image. The clever bit was using some CSS with a background image to track the message being forwarded (outlook adds some predictable CSS class names to the message when it reformats it for forwarding) and the use of an image resource that never actually loads, but does a sleep/redirect loop so it can track how long the message has been open (assuming images aren't blocked in the first place). Also another CSS directive to see when the message is being printed. At least, that's what I remember when I disassembled the code some months ago. If I can dig it up when I'm back in the office, I'll post it.
Though I think you have a much better chance of getting people to load images in a newsletter or marketing message where that's the norm versus a personal message where it might seem weird or unnecessary.
the use of an image resource that never actually loads, but does a sleep/redirect loop so it can track how long the message has been open
Hmm, very interesting. So they essentially make their server side script sleep for a few seconds, but not long enough that the client gives up waiting, then they send the client a redirect to the same script again. When the client stops requesting the fake image then it is safe to assume that the email is no longer being read.
That is a great idea, very innovative. I wondered how they were measuring how long the email was read.
Comments
I'm not actually sure they did much better than a regular image for tracking opens though I believe they also did a background-image. The clever bit was using some CSS with a background image to track the message being forwarded (outlook adds some predictable CSS class names to the message when it reformats it for forwarding) and the use of an image resource that never actually loads, but does a sleep/redirect loop so it can track how long the message has been open (assuming images aren't blocked in the first place). Also another CSS directive to see when the message is being printed. At least, that's what I remember when I disassembled the code some months ago. If I can dig it up when I'm back in the office, I'll post it.
Though I think you have a much better chance of getting people to load images in a newsletter or marketing message where that's the norm versus a personal message where it might seem weird or unnecessary.
the use of an image resource that never actually loads, but does a sleep/redirect loop so it can track how long the message has been open
Hmm, very interesting. So they essentially make their server side script sleep for a few seconds, but not long enough that the client gives up waiting, then they send the client a redirect to the same script again. When the client stops requesting the fake image then it is safe to assume that the email is no longer being read.
That is a great idea, very innovative. I wondered how they were measuring how long the email was read.