https://cuttlefish.io https://github.com/mlandauer/cuttlefish

Your proposal requires at least the status quo (aliased email address at signup), but the problem is it also requires cooperation of the receiver's email provider (e.g. gmail) and the sender's email provider. You are unlikely to ever see any new standard adopted by all major email providers, unless it came through a standards committee.

But your idea is interesting. Perhaps you could lower the cost of adoption by replacing the dependency on TLS/SSL with some sort of pgp signing scheme. This way all the "protocol" happens within the message body, so email providers do not need to adopt a new standard. As long as at least one website and one user implement the protocol, it can work without any cooperation from third parties.

As an aside, it would also be nice if password managers included functionality around generating temporary/isolated email addresses.

I rarely receive email spam these days. The spam I get is on my voice line. I'm getting several robocalls per day. If you have the skills to work on this stuff, I'd love to see a solution to phone call spam because email spam feels solved.

My greatest fear is that Google and Facebook will co-opt email and charge money for companies to get access. Google has already made some progress with this by selling ads in Gmail that look like email while pushing commercial messages in to other inboxes.

This is bad because it penalizes companies with low margins while shifting the advantage to those who are able to squeeze more money out of the users (you can see the effect of this on Google Search, Facebook, and now Amazon. It isn't pretty.)

I'd start with the "email postage" proposal—the one where either a proof-of-work or physical payment (which can also be digital, e.g. a Bitcoin private key) is required to get an MTA to take your message. This proposal was declared unworkable due to rendering high-volume transactional email impossible.

But then:

1. as you say here, divide everyone's email account into a set of "channels" (i.e. subaddresses in a+b@c form, that each have a corresponding message signing key), with one or more published or well-known channels, and then individual private channels for each contact/list, or for each conversation(!);

2. make MTAs aware of "channels", and extend both SMTP and email web services to allow users to configure their provider's end-of-line MTA, over-the-wire, to set the amount of "postage" required to message each channel they own. (This way, the MTA doesn't have to be aware of the distinction between private and public channels; they're just destination addresses with a stored config parameter.)

3. make the MTAs that use channels, reject any Internet message directed to the base address without a channel. (Messages generated by the MTA itself can arrive without a channel.)

4. Set the clients' default new-channel configurations such that public channels have a cost, and private channels are free.

5. In email clients, add a "Subscribe" or "Allow" action-bar item to messages that identify themselves as email-confirmation/newsletter-opt-in emails (presumably with a header), that, when clicked, creates a new channel for the sender, and replies to the message with the signing key you want them to use attached. (All this would be hidden from view; the reply message wouldn't end up in your Sent Items.)

6. In transactional-email-sending services like Sendgrid/Postmark/etc., create a distinction between "opt-in messages" and "ongoing transactional messages"; allow each account to send one "opt-in" email to each previously-unknown destination-address (and charge for this); but then, for that account, put that destination-address into holding state, where the account can't send them any "ongoing transactional messages", until the email-sending service receives the user's conversation key. (You probably want to allow accounts to re-send the opt-in email after a 24-hour-cooldown, though. Though they'd have to pay again!)

7. In any product/service backend that uses a transactional-email service, consider new signups unconfirmed until the transactional-service reports (by polling or webhook or whatever) that the user has replied with a key and is now in the "authenticated and free to send to" state.

A bit complicated in the initial changes, but in the ongoing state it's nearly ideal: it costs money to initiate contact with an address, or to continue pestering an address that doesn't want to speak with you, but not to send messages to someone that wants to hear from you. (Though, a user can "unsubscribe" from your list simply by telling their MTA to begin charging you to deliver to their channel again—maybe, UI-wise, by just deleting the channel. Transactional-email sending services could detect the bounced-with-payment-required delivery error, and put the user automatically into an "unsubscribed" state, which could webhook you to let you know!)

https://senderscore.org/ per https://news.ycombinator.com/item?id=9156312

http://whatismyipaddress.com/blacklist-check per https://news.ycombinator.com/item?id=11329371

http://multirbl.valli.org/ per https://news.ycombinator.com/item?id=11330382

This is because the big consumer mailbox providers often don't rely on public datasources for assessing reputation, and because reputation is tracked at the domain level, in addition to - or sometimes instead of - the IP level. For example, there have been some indications from Gmail that they no longer use IP reputation at all, starting a year or two ago.

And re: blacklists: +1 to Spamhaus, but in practice it's one of very few blacklists that have meaningful impact to net delivery.

(I do not have anything to do with the product or team behind it)

In years past, many RBLs would categorize IP Addresses by type. e.g. dynamic IPs assigned to DSL/Cable subscribers. This would enable a receving SMTP server to check if the email came from an ISP subscriber, rather than an email server. If so, it was usually a good guage that the email was "spammy", because it was sent by a subscriber's infected computer.

In this sense, it was (and may still be) possible to simply block, or at least score differently, email from any/all AWS Elasic IPs.

Neither, though, helps with checking if one of the big providers, like Google, would not like your IP. For those, you have to send an email and watch/parse the SMTP error responses.

In the case of Mailgun, you should be assigned an IP with a neutral reputation. For example, before dedicated IPs are reassigned we leave them dormant for at least a month, usually much longer, before assigning to a new customer.

Mailgun will do some chores for you, for a fee. If those chores are things you can do in your sleep, fine! Mailgun does nothing magic.

Until then, all is fine I agree.

Of course, if it's that important, then you'd be foolish to not have invested in a better solution, or to not have a proper SLA with a third party.