MSN today launched its Sender ID email authentication program for email sent to Hotmail users, DM News reports. Starting today, those emails for which the sender cannot be verified will be relegated to account-holder's junk email boxes. Yahoo has discussed a similar program but has not implemented it yet. The Direct Marketing Association alerted email marketers late last week of the program's implementation, and email delivery firms informed their customers yesterday.

"Messages that have not been authenticated will most likely be placed into a customer's junk folder or deleted altogether in conjunction with other spam filters," the June 17 DMA email stated. Microsoft announced the Sender ID program last summer but did not give an implementation date. And it has not communicated with the email marketing industry about it for several months, said Chip House, deliverability expert for email software firm ExactTarget.

The DMA and email delivery firms have urged their members to implement authentication programs for several months. "Compliance with authentication programs is a necessary step to protect both corporate brands and consumer confidence," said Jerry Cerasale, DMA senior vice-president of government relations.