No sooner do I sing the praises of owning a Yahoo! account and I'm forced to recant.
There's also a special option for "Please harass me by phone" and "Please kill more trees and deliver things to my mailbox at home."
To "opt out," login to your Yahoo! account and go to options > account information. Look for the link "edit your marketing preferences" in your member information. You can also try to jump directly to your preferences page at http://edit.my.yahoo.com/config/eval_profile
I think it may be time to forcibly remove Yahoo!'s exclamation point privileges.