Spam is also a problem. How do you do spam detection if you cannot read the message?
Behavioral methods might still work, particularly whitelisting/greylisting. Whitelisted senders will be passed, greylisted ones filtered. Spam can still be filtered locally with a key, if necessary, though that misses the leverage of delivery-time notification.
A notify-and-fetch dynamic might also work. Rather than delivering messages at send time, a notification that there is a message is sent, an on its strength, the message is later requested. Spammers have a much larger mail storage problem. Whitelisted senders might have mail delivered automatically. And collaborative spam filtering could mark and downrate spammer reputations before many recipients get to requesting the message, sparing them the spam.
Greylisting / teergrubing / delayed receipt (even just 1-2 retry intervals) cuts down much on spam as well.
Play the costs.
There are also distributed anonymous reputation systems, designed mostly for Tor / Web, though similar concepts for email might work. FAUST and Fair Anonymity:
It was difficult to implement and up against an already entrenched tech.
With Bitcoin I've been thinking of that idea again. Could a payment system on top of existing email be created? The receiver of the email could get the senders penny and Bitcoin might get a killer app that doesn't involve drugs...
But seriously, does it still fail if I have a local filter were I strongly prioritize emails of ppl who show up on the BC ledger?
If ppl in high tech start doing this to lower their own email burden, I can envision normal business ppl copying the technique to lower their own.
It would also put a slight amount of friction in place for contacting people out-of-the-blue (when e.g. sending fan-mail to famous people)—but the fact that some stranger paid $0.05 to say something to you could also make you just fractionally more interested in what they have to say.
On the other hand, for accepting bug reports, help tickets, etc., there'd have to be some kind of email equivalent to an "800 number", that is free to initiate contact with. Either that, or a lot of behind-the-scenes pairing magic to get your email address into the directory service of all the products and services you use.
For me there's an annoying aunt who periodically send the latest get-mad-at-this email.
Or, how many times do we receive a mass email from friends who use CC instead of BCC and then we're flooded by everyone's replies?
If you're in my address book, then you should be charged more!
Spam is hard because there's no manual filter you can write that targets "everyone you don't know", without removing the ability to be reached-out-to by real people who have a genuine desire to tell you something you care to hear.
It's possible the botnets are strong enough to create Hashcash or mine Bitcoin and still spam enough to annoy us... and it would probably take either Google, Yahoo, or Microsoft announcing they would stop accepting legacy emails (where "legacy" could just be ones without Hashcash or BTC), for anyone to make a change.
And a fee will also never, ever fly for email, being not a matter of entrenched tech, but rather one of artificial scarcity, being the reason for why SMS is dying.
I'm not proposing paying a third party to send me email. You'd be paying me for my scarse resource - my time and inbox space
They make it near impossible for bigger hosts not to get blacklisted unless they fully comply with spamhaus.
https://www.virusbtn.com/blog/2011/10_13.xml
It's worth noting that spamhaus had no real reason to do this as they had already blocked the hosting company a2b was providing bandwidth to, so blocking all of a2b didn't actually stop any more spam.
Zen is far far from not blocking any real email, they regularly block large ISPs that refuse too indiscriminately drop customers on their request.
> Update: Spamhaus has now commented on the case in a blog post, explaining how Cyberbunker (also known as CB3ROB) has been involved in hosting malware and phishing sites. Ironically, this very week Spamhaus has been working with the Dutch hi-tech crime unit to investigate the criminal activity hosted by Cyberbunker and routed by A2B.
This is really your example of false positive blocking?
What exactly justified blocking A2Bs IP space here?
Spamhaus is a really shady organization with a history of unethical behavior, look up the nic.at fiasco as another example... Or just ask anyone who works in hosting.
That's exactly what people want from something like the SBL, which is why it's used by so many people.
Your reference to nic.at is weird - again they were providing services to a bunch of criminals.
When complaining about false positives it'd be really helpful if you could point to people who aren't fucking scumbags who are getting blocked.
Probably not be that hard to sort out.
That's actually the best idea for spam reduction I've heard so far (which is not really saying a lot). Half a second won't be noticed by a normal user, but it will be noticed by people sending thousands or millions of emails.
Sure Spammer will install large GPUs hashing rigs and still manage to send thousands of emails per second, but it would cost them a lot more than it does now.
One problem will be phones, a hash that takes about half a second on a desktop will take tens of seconds on lower end mobile phones, which is hardly unworkable but you could offload the calculations to a 3rd party server (with a large GPU based hashing rig) for say a fraction of a cent, especially if the email contents were encrypted by the phone before hashing.
And it could be introduced without breaking the email system. Initially the presence of a hash will just be used as an additional spam filtering signal, but as support grows over time you can make it harder and harder for emails without a hash to get through.
Like bitcoins, you would need a mechanism to increase the required work over time, though it could just be ad-hoc based on what mail server operators choose to accept.
[1]: http://www.hashcash.org/ [2]: http://www.hashcash.org/bitcoin/
But we are talking about $0.0005 (0.05 cents) worth of hashing on CPU systems per email. With GPU based hashing it should be 50 times cheaper. If your team has 1 million customers, and can't afford the $10 to pay a GPU based hashing service to hash 1 million emails for you, you might have a bigger problem.
I suspect the biggest issue for such a scheme is $10 for 1 million emails is potentially still profitable for spammers while being at the limit of how much cpu time you can expect to waste for regular (particularly mobile) users. And that's before you consider the possibility of ASIC hashing for emails.
what other costs can we impose? the email lists that spammers harvest stay valid for a long long time, what if they were invalidated faster? to have a high hitrate on their lists they'd need Google scale crawling capabilities, which kinda then defeats their point of trying to make a living from spam.
why are we converting long term relationships with servers(email id and password to login) into relationships with every Tom on the Internet(no control over who can reach you, hence you are in a relationship whether you like it or not)? Do we still have to remember emails or phone numbers, aren't they names in an address book already? why don't we just move off email, use a new system that uses long, hidden alphanumeric ids to identify relationships between people that can be invalidated by either party?
invalidate unnecessary relationships faster = invalidate spammer lists faster :)