Hi, spywaredr! Thanks for the input. I never saw it as insulting... hmm, interesting. Whenever I got work mail (from email addresses I know) I never gave it a second thought and just clicked on the confirm button, so I never considered it as offending when it is the other way around.

Also didn't know about the ++info on the header. Normally, whenever a recipient would be considerate enough to confirm receipt, I'd just get a really short template email saying so, like to: from: subject: receipt date: something like that, nothing overly informative. Maybe it's with my settings.

For personal mail, I don't use it. It's just useful for work mail wherein I either need a documented confirmation of email receipt or just to know if the email they're expecting reached them because some clients need to play tag (calls, follow up email, sms) for me finally get a "oh yea, got it three days ago. it's a good thing you called about that". And I'm not talking about bugging them with unsolicited email, I'm talking about email that they know need their attention. Normally, I add a polite "Kindly confirm receipt of this email." note at the end, but only a tiny some do so. Exacerbating the issue is our current server (though we're currently fixing it by transferring webhosts soon) which is unpredictable. At times it's prompt with email delivery, sometimes, it gets delayed by hours, sometimes even days and there are few few times not at all.... so those are the reasons why.

That said, maybe it's not a good idea to make it auto sent, but make them click on the button (just one nothing to choose from) or something so they know they're actively confirming.

Using the Thunderbird feature, I actually don't get it why one would click on cancel instead of confirm button (meaning it's not laziness) when there's nothing extraordinary in the email content, just normal work sutff (studies, quotations, billing, discussion of projects)... I actually find it inconsiderate esp when there's a "kindly confirm receipt of this email" at the end, but that's them.