Yahoo! changed its privacy policy last week, contemptuously exposing all of its registered users to third-party spam, marketing offers and cold calls that they'd previously said they didn't want.
As from now, Yahoo! mail users are exposed to a dozen unwanted "Special Offers and Marketing Communications", and users who've left their phone numbers with the portal will discover that they've been "agreed" to cold calling and junk snail mail, for good measure.
You can delete your Yahoo! account here if you want.