Reporting spam from a Yahoo email account
If a spam email you received was sent from a yahoo address, you can complain to Yahoo.com directly. Just forward the message, including all its headers, to one of the following mailboxes:
mail-abuse@cc.yahoo-inc.com
ph-mail-abuse@cc.yahoo-inc.com
network-abuse@cc.yahoo-inc.com
abuse@yahoo.com (they say that this mailbox gets filled up and bounces incoming messages sometimes, so try the other emails before using this one)
There. A more constructive technique, rather than helplessly hating the spammer 