Why isn't there a handshake protocol for email? Each client whitelists email addresses that your client can recieve? This drops spam to zero. You OPT in to newsletters, you can OPT in to "rewards" emails from companies. To be revoked at all times. Workflow: Want to recieve an email from an address, go to handshake tab, enable their address. The list of handshake addresses is searchable Emails recieved prior to handshake are bounced. You CAN set it to open, but then you lose spam mitigation. Any reason why most email clients don't operate this way?