Calling the proposed service an "e-mail tax," the coalition is trying to drum up opposition among AOLs members, some threatening to encourage a boycott if AOL goes ahead with the service.
The coalition includes groups as diverse as the AFL-CIO, the Humane Society of the United States, the Consumer Federation of America, Oxfam America, Computer Professionals for Social Responsibility, the Democratic National Committee and Gun Owners of America.
Under the guaranteed delivery service, AOL would use Goodmail Systems CertifiedEmail and charge customers to ensure that their messages bypass the filters set up to protect AOL members from spam.
The coalition estimates that mailers would pay between one-fourth of a cent and one cent per message.
For an organization like MoveOn.org Civic Action, which has hundreds of thousands of members who use AOLs e-mail service, the guaranteed delivery system could cost thousands of dollars each week, said Ely Parisier, executive director, in a conference call with reporters Feb. 28.
While some nonprofit groups could afford the charge, others say they could not.
"AOLs e-mail tax could potentially block every AOL subscriber suffering from any form of cancer from receiving potentially life-saving information," said Gilles Frydman, head of the Association for Cancer Online Resources.
"Cancer patients may not be able to get resources simply because a nonprofit like ACOR, which serves more than 55,000 cancer patients and caregivers every day, cannot afford to pay AOLs fee."
The coalition is concerned not only about the cost to nonprofit organizations but also about the potential for fundamental changes to the culture and architecture of the Internet.
The fear, coalition members said, is that the ISP would spend less time and money keeping spam filters up-to-date and would instead encourage more senders to join the guaranteed delivery system.
"Its the first step onto a slippery slope that will dismantle the net freedoms that Americans have come to know," said Timothy Karr, campaign director for Free Press.
"The flow of online information, innovation and ideas is not a luxury to be sold off to the highest bidders."
Coalition representatives said that they are also concerned that other links along the e-mail chain would follow suit and being charging for services.
"[AOLs proposal] introduces the machinery to tax individual e-mails," said Danny OBrien, activism coordinator at the Electronic Frontier Foundation.
"You really dont know where this thing leads. Essentially peoples inboxes are being held to ransom. You build a machinery where you can charge for e-mail, and everyone wants a cut."
Yahoo officials have also expressed interest in a guaranteed delivery service, but the coalition is not targeting it because Yahoo appears to be much more tentative about it, OBrien said.