Deleting Yahoo! account

Deleting Yahoo! Mail account, Removing Yahoo! Mail Account, Cancelling Yahoo! Mail Account
Deleting Yahoo! account, Removing Yahoo! Account, Cancelling Yahoo! Account
Deleting Yahoo account, Removing Yahoo Account, Cancelling Yahoo Account

How ever you want to say it, it is simply described here:
Link

My Version would be:

1. Go to: https://edit.yahoo.com/config/delete_user
2. Login / validate
3. Done!