This does not apply to tracking pixels - the technology used here is completely different.

What you mention is the ability for your email client to send a "that email was read" message when you send an email with such a request.

Yes. They are saying that if people really wanted to tell you when they open your email, they could enable it. However, they don’t. Throwing tracking pixels in are really a means to circumvent the wish of the recipient.

...which most people have turned off, for good reason.

This is why people build features like this. They want to track their email to you, and they want to do it without your consent.

The default setting for such feature is to ask the user.

It makes the whole interaction more creepy, moreover, I don't think that a lot of webclient support it (or even Smartphone apps).

It's kind of a dying feature.

> The default setting for such feature is to ask the user. It makes the whole interaction more creepy.

I never considered that a consensual request prompt could be considered 'more creepy' than non-consensual spying. What about that interaction upsets you? Simply knowing that someone wanted to do it?

My general heuristic is that if people knowing that you're doing something to them would be a problem, then you should at least consider that it might be inherently creepy to do it.

The reason people are creeped out when you ask them whether or not you can monitor them is because they don't want to be monitored. Skipping that question and tracking them without their permission doesn't make it less creepy, it makes it more creepy.

I remember both Roundcube and Squirrelmail supporting them, and they are quite common.

At the risk of explaining the joke: I'm guessing you mean that option is the reply button? :).

No, there actually exists an email header to request a notification email to be sent back whenever the original email is read. This header exists since at least the 90s, and for instance Thunderbird has options to both set that header, and to honor that header (sending the notification emails). I vaguely recall that the default, at least when I last configured Thunderbird, was to not add that header, and to ask before sending a notification email.

Oh, that. I completely forgot about it! I always liked it that in the mail clients I've used, this was always voluntary.

Does it work the same for all clients?

For Outlook and Thunderbird yes, I am not sure about the support in Apple Mail and webmail clients.