I have just discovered the worst thing ever

I am interested in this from a development stance, and wonder if there is any way around however it works. I have no interest in installing this myself. Does this work just for web-based clients, or does it also work if the "target" is using, say, Outlook on their computer and their email address is not some gmail or yahoo account, but a corporate account (like on an in-house Exchange server)? I think it probably doesn't matter, but I don't know. Very disturbing since this seems to expose a massive privacy vulnerability in how email is relayed. I definitely do agree with the people who have expressed privacy concerns. The most disturbing thing to me is that most people don't know that this information is accessible, and therefore can't make informed decisions based on that knowledge.

But I also don't judge you, OP. And I'm sorry this is causing you so much distress. I guess the only outcome from sending an email that wouldn't be bad to you is actually receiving a reply? That's understandable. But maybe "irrelevant" is a bit of a leap for you to make just because she hasn't read or has read but not responded to your email. She could be busy with other things right now. Or, to be honest, she could be like me and she could absolutely loathe emailing and have to psyche herself up to do it. I am currently a student, but at my last office job, I used to dread and procrastinate checking my email. Replying was no better. And it had absolutely nothing to do with my coworkers, or me not wanting to deal with them or whatever they needed from me, or anything like that. I just really don't enjoy emailing and kind of hate it, actually.

When I first heard about these trackers on here, I was curious how they worked. The one I read about used a small image file that would not be visible in the email (think like a 1 pixel image that would look like a tiny black or white dot). The image file is stored on a remote server. When the email is opened, the image file would be accessed and the tracker would know when and where the web server traffic came from. I'm guessing that if the email recipient doesn't have HTML turned on for email, the tracker probably wouldn't work. If the recipient was suspicious and tech savvy, they could examine the source of the email and find the embedded image file. They could also note the packets being sent from their computer and if they found an image file being retrieved from emailtracker.com they could figure out what's going on. I doubt most people would be able to figure this out, but it also wouldn't be hard to get a tool to defend yourself against being tracked like this.

Ok, that's worse than I was imagining and I am definitely judging the person or team who developed such a tool.

Definitely agree with this. There could be lots of reasons an email has been opened but hasn’t been replied to that have nothing to do with a T not caring or ignoring you.
I get tons of work emails, but attention-wise it takes a lot more for me to compose a response than to read a message. I have to wait until my brain is cooperating to write a quality response.