Hi DW,
I haven't had a chance (yet) to research this more but am definitely willing to consider it if you can explain it to me.
I believe I looked at that site before, here's the problem I see with it, at first glance, from the website:
Simply add: .readnotify.com to the end of your recipients email address
It seems like they are asking you to add that, AND then to send everything through their servers... this would never work... it doesn't seem it's possible, and I don't believe it ever WILL be possible to add this type of tracking - UNLESS someone at microsoft/yahoo/aol get's smart about setting up/creating 'SENDERID' features which has been talked about for years... Even if they do, I don't know if it would allow OPEN tracking...
The ONLY way I know to do this is with an invisible .gif file embedded in the message which has several problems as we've already discussed in this post... hence my opinion:
It is IMPOSSIBLE to reliably and safely track opened email...
Please don't rack your brain on it, you've got much more important things to work on ... Split-Test tracking, etc.... (can't wait for that)...