How I'm spying on you

What Substack does each time you click on an email link

You may have noticed that Substack—the system I’m using to send you emails—replaces all links in the emails I’m sending you with links to Substack. It does this in order to spy on you and provide me with useful statistics about what my readers are doing. It doesn’t just give me statistics about my readers as a whole; it also gives me much information about each one. Here is an example of what it shows me for a reader (myself actually):

As of February 2021, Substack doesn’t offer the option to deactivate this feature, and I can’t convincingly promise that I won’t look at your file (though I very rarely, if ever, do, since I’m busy with more important things). If you dislike this feature, you need either to never click on email links (which is inconvenient) or to unsubscribe from the list (which is perfectly understandable). Or, after receiving an email, you can go to and read it there and click any links you like.

Does Substack know if you’ve opened my emails if you don’t click any links? This depends. Some email clients, such as Thunderbird and K9, by default do not show images in the email—you have to click a button that says something like “Show remote content for this message”. In this case Substack doesn’t know you opened the email unless you click the button. But if your client shows images immediately, then Substack knows, since the client makes a request to Substack in order to download and display the images.

Fun fact: Google Search does more or less what Substack does—it records which search results you clicked on—except that it’s a bit worse than Substack, because the search results are links that point to various other sites, not to Google. However, there is some JavaScript that, when you click on the link, it also notifies Google that you’ve done so. AdBlock stops this from happening.