Yes, but many email marketers know this trick and they just strip out the comment or tag, or else make you give them an address that doesn't have it.

Even worse: Some of them happily accept such addresses, but some time later, silently drop messages to you while claiming that they were sent.

The obvious solution would be to use [email protected] and treat [email protected] as a semi-spam folder

Yup, since I'm using my own domain domain I use kevincox@ for public sharing and generated emails for sharing with companies. Therefore there is no obvious path from the email I give them (which bypasses the spam filter and can be revoked) to my general email address. Although it is easy to find my general address online it is fairly heavily spam-filtered. And unknown address is subject to an very harsh filter if it wants to end up in my inbox.

So basically there are three tiers:

- Single relationship emails. Guaranteed delivery until revoked.

- General inbox.

- Unknown to addresses, unlikely to hit the inbox.

(The address are actually signed and blacklisted rather than generated+revoked but that is just an implementation detail)

And spammers will happily remove those bits from the address.

Comments aren't semantically meaningful, anyone can strip them out without changing the meaning of the email address.