What other email services offer a true anti-spam whitelist feature?

[Ted C]

Spam is making me hate using email. Since Yahoo doesn't offer a whitelist feature that allows only email from people already in your address book I am wiondering if anyone can offer the names of alternate email services who do? People couild then stop SPAM dead in its tracks. It's a shame really since several years ago Yahoo at least used to have a terrific feaure that displayed all email not in your address book so they can be easily scrutinized and blacklisted.