[kazinator]

This is just anonymizing of addresses. Through your throttle account, connected to a convenient browser extension, you can conveniently generate throwaway addresses which forward to the real inbox. These addresses can be shut down and since they are unique, they identify misuse.

Anonymizing isn't new. For instance Craigslist generates an anonymized e-mail address through which people interested in your ad can contact you. (Of course, if you reply to it, then you reveal your real address.)

People who run their own mail domains do this kind of thing on their own.

I have the following system: the local part of the e-mail address has a four digit security code. If I give such an e-mail address to some vendor, it serves two purposes: the address bypasses spam checks, so I'm sure to get the e-mail. (Usually transactional e-mails are important and not easy to re-send.) Secondly, I can change the code to shut down senders who abuse the the address.

Some banks offer throwaway one-time-use credit card numbers linked to your real credit card. That is very similar to this.

[saltyshake]

"Of course, if you reply to it, then you reveal your real address"

Do you ?

I am pretty sure it redirects everything through the CL email proxy and the only way for them to know your real email address is for you to give it to them (or they guess it from your "Name" which the CL relay copies from your email).

[kazinator]

My bad! Sorry!

CL performs a decent, two-way anonymization. When you reply to a listing's anonymized e-mail, your own e-mail address is anonymized (just not your name, which I think comes from your From: header or SMTP envelope address? In any case, you control that).

Furthermore, the originating SMTP paths are mutually concealed by CL. You don't see how the mail arrived into CL, just how it came from CL to you; i.e. it's completely remailed.

Lastly, even the Message-ID is rewritten. The originator's message ID could contain clues about the mail domain and such; CL replaces it with their own.

Quite probably, they strip away the signatures from bodies as well; those could inadvertently leak identity bits.

[Source: I searched my inbox for some CL interactions, several years old, and examined the headers.]

[banterfoil]

correct

[Veratyr]

The concept isn't new but the usability is. This was very hard for normal people to do until very recently.