US Internet giants to start "

America Online and Yahoo are set to begin using a system that gives preferential treatment to messages from companies that are willing to pay to guarantee the delivery of these messages, AFP, citing a New York Times report, said.

The AFP report said the plan meant companies would soon have to buy the electronic equivalent of a postage stamp if they wanted to be certain that their e-mail would be delivered to many of their customers.

The report said the senders must promise to contact only people who had agreed to receive their messages, or risk being blocked entirely.

AOL and Yahoo said this would help them identify legitimate mail and cut down on junk e-mail, identity-theft scams and other scourges that plagued users of their services, according to the New York Times.

Observers said the two firms stood to earn millions of dollars a year from the system if this would be widely adopted, the report said.

While AOL and Yahoo would still accept e-mail from non-paying senders, the paid messages would be given a special treatment, the paper said.