How do I know who leaked or sold my email (and how you can too)

Hi, internet! I'm writing this short blog post because I keep reiterating the method of learning who sells or leaks my data to different people. I'm writing this once and will simply share the link to this post whenever I need to share the info.

By now, you're probably familiar with email aliases. For instance, you can have n+google@bdut.ch or n+meta@bdut.ch. However, spammers are smart enough to strip aliases from the leaked or sold data — so aliases don't work.

Instead of using aliases, I'm proposing a technique that can't be fooled by spammers. I'm not the one who came up with it. I found it on the internet, used it, and I'm sharing it with you.

Use custom domain name email addresses with catch-all. Instead of repeatedly signing up for services with the same email (e.g. n@bdut.ch), put the name of the service as part of the email before the @ symbol. So if I sign up for Grammarly, it's grammarly@bdut.ch; Facebook — meta@bdut.ch; Google — google@bdut.ch; Farcaster — farcaster@bdut.ch. It works even in the most unobvious places. For instance, I use it for my massage therapist, all loyalty programs and credit cards.

Because you use catch-all, all the emails to any name before the @ symbol will go to the primary email (it's n@bdut.ch for me). You will never miss a single email this way!

I'm using Google Suite because I have a corporate subscription, but I'm sure there are free alternatives (or self-hosted ones like mailinabox.email).

Now you are also aware of this incredible way of knowing precisely who leaks or sells your data. Go use it and publicly shame the companies that do so!