Redmond, Wash.—Microsoft began this week to notify its Hotmail customers when the Sender ID protocol is unable to verify the authenticity of an e-mail. Messages not in compliance will not be delivered to the intended recipient.
Sender ID is among a handful of authentication protocols being adopted by ISPs and e-mail marketers.
"Compliance with authentication programs is a necessary step to protect both corporate brands and consumer confidence," said Jerry Cerasale, senior VP-government relations at the Direct Marketing Association, in a statement. The DMA strongly supports authentication adoption.