TECH TALK: The Death and Rebirth of Email: Solution Ideas (Part 6)

Kevin Werbach advocates the use of white-lists to battle spam. This will, in effect, change email from an open system to a closed system. He wrote about this in Slate (November 18,2002):

Whitelists typically allow e-mail from everyone in a user’s existing address book. Other, unknown senders receive an automated reply, asking them to take further action, such as explain who they are. Or senders may be asked to identify a partially obscured image of a word. A person can make out the word, but automated spammer software can’t.


Like it or not, the only way to kill spam is for an element of e-mail to die as well. There’s always been something charming and casual about e-mail. The informality comes through in the style people use to write messages, but also in where they send them. You’ve probably sent an e-mail to someone you’d never call on the phone, approach in person, or even write a letter to. Losing this aspect of e-mail is a shame, but it’s inevitable. E-mail will become more like instant messaging, with its defined “buddy lists.”


An application which builds on Kevins idea further is Tagged Message Delivery Agent (TMDA):

TMDA is an open source software application designed to significantly reduce the amount of SPAM (Internet junk-mail) you receive. TMDA strives to be more effective, yet less time-consuming than traditional SPAM filters. TMDA can also be used as a general purpose local mail delivery agent to filter, sort, deliver and dispose of incoming mail.

The technical countermeasures used by TMDA to thwart SPAM include:
– whitelists: accept mail from known, trusted senders.
– blacklists: refuse mail from undesired senders.
– challenge/response: allows unknown senders which aren’t on the whitelist or blacklist the chance to confirm that their message is legitimate (non-SPAM).

This combination was chosen based on the following assumptions about the current state of SPAM on the Internet:

1. You cannot keep your email address secret from spammers.
2. Content-based filters can’t distinguish SPAM from legitimate mail with sufficient accuracy.
3. To maintain economies of scale, bulk-mailing is generally: an impersonal process where the recipient is not distinguished. and a one-way communication channel (from spammer to victim).
4. SPAM will not cease until it becomes prohibitively expensive for spammers to operate.

Tomorrow: My Solution Ideas

TECH TALK The Death and Rebirth of Email+T

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Rajesh Jain

An Entrepreneur based in Mumbai, India.