Fastmail supports subdomain addressing, such that instead of "user+service@domain.com" you would use "service@user.subdomain.com", which will forward the message to "user@subdomain.com" and even file it into a folder for "service".
You can also create free aliases on a completely different domain, and I think they have a plugin with 1Password to do this for each login you create.
I setup a sequence of letters which makes it completely unobvious for anyone who doesn't know the sequence
If you own your own domain, it's trivial for them to notice that it's a vanity domain for a single user or small group.
The only way to hide is to have thousands of friends with diverse interests using your domain.
Trivial to a human looking at the data set, but it's something the algorithm would have to be trained to recognize.
Not really - in practice the tracking system can have a list of email providers and treat every other domain as one user (especially ones with catch-all setups).
I don't think it's trivial at all? I sign up with random first names and last names, my email address doesn't have the actual company name and I don't think there's that many people with vanity domains to justify adding code to track this use case.
For historical reasons I use a dash. This works just fine 99+% of the time, but very rarely a site will not allow a dash in emails.
Thank you - finally someone who knows that it was always a dash.
What do you mean? What was "it"? Subaddressing semantics has always been at the discretion of the email service provider.