[Hooray_Darakian]

> Every time I give out my email address, behind the scenes a single-source permission/token is created. 2. Thus, that one source is able to send me email, from the email address they specified at the time. 3. But if they hand over the permission/token to anyone else, email from that new source will automatically bounce/be marked as suspect/flagged (my choice in configuration).

Do you mean hand out in a digital sense or on a business card? I'm not sure you can support the business card use case if you implement that.

[all2]

I assume that business cards would have a unique email/end point to allow for this case, kind of like how gmail and others allow you to add +<stuff> to the end of your email address. So you'd have a set of "business card" emails + rules that would allow only the first sender to send emails to that address (for example).

[mminer237]

So each business card would have to be unique with a unique address? I feel like it is generally considered unprofessional to have an email address with random letters in it, not to mention, you'd need a special business card printer to handle that.

[ivan_gammel]

The email address can be user-friendly, but card can also include an unique code similar to product serial numbers, that is redeemed with the first message.

E.g. „Max Mustermann“ <ABCD-1234-XYZW|[e-mail]> is a valid email address with unique code part.

[gcanyon]

I think yes, this would be required. An email address with random characters in it for no reason would certainly be questionable, but if the use case I'm proposing becomes at all known it would be much more understandable I think.

[jrky]

>So you'd have a set of "business card" emails + rules that would allow only the first sender to send emails to that address (for example).

Simple but genius! I love it :-)

[gcanyon]

Yep -- I wasn't thinking of business cards for this, but something like this would be required I think.

[gcanyon]

More digital -- I haven't had business cards in ages. But even in a card case it should be possible to: 1. print cards with a unique token/whatever on each card (I get that this isn't the same as old school cards that have to be identical) 2. limit any given token to 3 uses (or similar)

[Hooray_Darakian]

I think the more practical issue is that if each business card has its own single use token then your printer is doing one copy of each card. Doable, but not how any business card company is setup today. I do get the desire for this sort of thing, but I also think most users of email treat an address as a static entity.