They call them “read receipts”, and functionally they do work like read receipts, insofar as they indicate when you read a message. But real email read receipts are under the recipient’s control, and they’re a simple binary flag, read or unread — they don’t tell the sender how many times or when you view a message.
This post was about Superhuman in particular, but it applies to all email services using tracking pixels. Email has an official “read receipt” feature, a feature that is under the recipient’s control, as it should be. These spy pixels are a surreptitious circumvention.
I know that mailing list software generally includes tracking pixels. I don’t think that’s ethical either. On a personal level, though, with Superhuman, tracking when and how many times a recipient views a message is simply absurdly wrong.
It’s also something the vast, overwhelming majority of people don’t even realize is possible. I’ve told the basic Superhuman tracking story to a few people over the last few weeks, and asked whether they realized this was possible; all of them expressed shock and many of them outrage as well. Email should be private, and most people assume, incorrectly, that it is. You have to be a web developer of some sort to understand how this is possible. Email is supposed to be like paper mail — you send it, they get it, and you have no idea whether they read it or not. It bounces back to you if they never even receive it, say, because you addressed it incorrectly. The original conception of email is completely private.
But also, the original conception of email is that messages are plain text. No fonts, no styles, just plain text, with optional attachments. But those attachments are embedded in the message, not pulled from a server when the message is viewed.
Once we allowed email clients to act as de facto web browsers, loading remote content from servers when messages are viewed, we opened up not just a can of worms but an entire case of canned worms. Every privacy exploit for a web browser is now a privacy exploit for email. But it’s worse, because people naturally assume that email is completely private.
It’s a little depressing re-reading this piece today. Everything I’m arguing today, I argued then. Email privacy in the face of these trackers remains an industry-wide disgrace.