criquet's Journal: Three pronged approach to elminate ALL spam.

1. Dynamic, temporary/expiring email addresses. If the address includes a plain-text date of expiration, it will allow spammers to know that the address is no longer valid so don't bother sending it.
      http://www.mailexpire.com/
      http://www.spamgourmet.com/
      e.g.
          [e-mail] will be good until January 13th, 2004
          [e-mail] will be good for the entire month of January 2004.

2. Single-sender (user/domain) addresses. They allow only one sender or domain. This is similar to point 1 except that the address is a hashed string that can be used to verify that the sender is the allowed sender. This is useful for registering with mail lists.
      e.g.
          XDuquXQMcZ/[e-mail] will only allow [e-mail] emails to pass.
          [e-mail] will allow any @slashdot.org email.
      Optional:
          - Can be prepended with a string to indicate that the address is this type of address so don't waste bandwidth sending to it unless you know it will get through.
          - The Hash can be a hash of an encrypted value to add extra protection.

3. Everyone digitally sign ALL personal/business emails and include the recipient and sender addresses within the signature . If an email doesn't contain a valid, verified signature, it doesn't pass.

These measures don't imply that you can't retain open addresses that allow all email to pass.

The single-sender addresses must be encrypted

[criquet]

because, otherwise, spammers will simply generate the hash for their bogus sender address.