With more than 50 million phone numbers already on a federal do-not-call list, many e-mail users are eager for a no-spam counterpart.
But don't hold out much hope, even if one is created. Phone and e-mail systems - and the marketers who employ them - are fundamentally different.
"It's beyond even an apples-to-oranges comparison," said Nicholas Graham, a spokesman for America Online Inc.
Even supporters say a no-spam list would be no panacea.
"I don't think anyone out there is going to tell you that a do-not-e-mail registry is going to be as effective as a do-not-call registry," said Matthew Prince, co-founder of Unspam LLC, a Chicago startup that developed technology to run such an anti-spam list.
Not that the cautions are stopping the efforts.
Sen. Charles Schumer, D-N.Y., has a bill to create a national do-not-spam list. State senates in Louisiana and Michigan have passed similar legislation, and bills have been introduced in other states. Violators could be fined - and in Michigan, even sent to jail.
An industry trade group, the Direct Marketing Association, already keeps a no-spam list of 700,000 e-mail addresses that its members are asked to heed. Also, at least three private companies started their own no-spam lists this year. Two of them charge the public for inclusion.
But these lists have no enforcement power.
"When the do-not-call list hit 30 million names, we just said, `Wow,"' said Tom Jackson, chief executive of Global Removal Inc., which charges $5 per individual e-mail address.
Bryan Hunter, who runs the $9.95-a-year Remove.org, claims lists such as his help marketers better target pitches. "They realize these are people who aren't going to buy their products," he said.
But John Levine, board member of the Coalition Against Unsolicited Commercial Email (CAUCE), dismisses such companies as toothless. Without the legal standing of a government list, such private efforts "range from naively ineffective to complete scams," he said.
Michigan Attorney General Mike Cox has threatened a deceptive-marketing lawsuit against Remove.org. The company has since toned down its Web site, but an investigation is continuing.
Meanwhile, the chairman of the Federal Trade Commission, which runs the do-not-call list, doubts whether a government-run counterpart for spam would work.
E-mail systems are spread out around the globe, and information about the e-mail sender is easy to fake. The phone network is centralized and regulated, tends to follow national boundaries and has fixed circuits that are less prone to spoofing. Together, that makes telemarketers easier than spammers to catch.
People also change e-mail addresses more frequently than phone numbers, making any no-spam list quickly old.
And while telemarketers are largely businesses pitching legitimate products, spammers are more likely to promote deceptive get-rich-quick or get-anatomically enlarged-quick schemes.
If spammers aren't following consumer-protection laws now, they likely won't adhere to any lists, said Bob Wientzen, chief executive of the Direct Marketing Association.
"We're very concerned that the American public might be sold a bill of goods," Wientzen said, acknowledging his group's own list has done little to stop spam.
A no-spam list also raises security issues: Just think of what could happen if a spammer got hold of such a database. Prince and others, however, say such lists can be encrypted.
Critics also say spammers abroad would be difficult to locate and subject to U.S. laws. However, Ray Everett-Church, counsel for CAUCE, is unfazed.
"The server may be in China or Brazil, but the person advertising in that e-mail is most likely either based in the United States or has some jurisdictional tie to the United States," Everett-Church said.
Where no-call and no-spam lists converge is in the debate over their constitutionality.
A federal court in Denver has ruled that the no-call list violates the telemarketing industry's free-speech rights. An appeals court, however, has temporarily blocked the order.
David Sorkin, a John Marshall Law School professor who tracks spam laws, said a no-spam list would likely face similar challenges. But he notes that junk-fax prohibitions have survived such tests.
As for whether it would work, Sorkin is skeptical. He doesn't believe it would do much to stop today's breed of spam, though it could prevent e-mail marketing by legitimate businesses that haven't quite taken advantage of the medium yet.
So after all that, you'll still see your mailbox filled with Nigerian - or is it Liberian? - investment opportunities. But at least your phone won't ring as often while you hit the delete key.
By Anick Jesdanun