ASHINGTON, May 2 — There probably isn't a "Wendy" behind the e-mail offering a way to "lose 30 pounds in 30 days." And it seems unlikely that the real vendor of the "Iraqi most-wanted playing cards" is really named "Doc Holiday."

Most unwanted bulk e-mail, or spam, is sent under forged names and addresses, making it hard to track down the real senders. At a three-day forum that just ended here on spam, sponsored by the Federal Trade Commission, there was a consensus that spam was increasing rapidly this year. But there was little certainty about who was behind it.

That makes it hard, of course, to bring "Doc Holiday" to justice. But more important, understanding who is sending the messages is crucial to figuring out what the right policy should be to deal with spam.

The Direct Marketing Association and AOL Time Warner's America Online, among others, say the majority of the truly revolting bulk e-mail comes from a network of 150 to 200 master spammers. This camp is calling for narrowly written laws, like Virginia's new anti-spam law, with tough penalties for fraudulent e-mail, to go after these spam kingpins. The Can Spam Act, which was recently introduced in the Senate, is another law this group favors.

But many others involved in the Internet see thousands of spammers, from teenagers in basements to legitimate businesses, that become too aggressive in their e-mailing. Fighting these lesser offenders, they say, requires different tactics meant to force marginal players into legitimacy, such as disclosure rules in the anti-spam legislation proposed by Senator Charles E. Schumer of New York and Representative Zoë Lofgren of California, both Democrats.

And there are some who argue that an e-mail box is inherently more private than a postal mailbox and that nearly any marketing pitch that has not been clearly requested by the recipient should be banned. This view, as popular among some of the Internet elite as it is detested by the marketing industry, has few backers in Congress or state legislatures. But it has led some longtime anti-spam activists to oppose legislation like the Can Spam Act because it would have the effect of legitimizing some unsolicited e-mail. The Can Spam Act, for example, would permit a company to send e-mail to someone with whom it has no previous relationship as long as it does the following: clearly identify itself and what the message is; say what it is an advertisement for; and offer recipients a method to say they do not want any more offers from that sender.

"We are at a tipping point with spam," David Sorkin, associate professor at the John Marshall Law School in Chicago, said in a panel presentation at the forum. "But, with the bills we see now, I fear we will be on the wrong side of the cow."

Senator Conrad Burns, the Republican of Montana who is one of the authors of the Can Spam Act, said in an interview that he wanted to create a bill that balanced the rights of e-mail users and legitimate marketers. But in any case, he added, it is impossible to push a tougher bill through Congress. Indeed, a virtually identical bill passed the Senate Commerce Committee last session but languished on the floor.

"To those who would stand back and criticize, I say `come on down and try to pass your bill if you think it looks so easy,' " he said.

The Direct Marketing Association, the trade group that represents companies that send postal mail and e-mail, argues that the few are ruining e-mail for the many. "While there are 100,000 individuals who are causing the spam problem, there is a huge volume that comes from a relatively small group of companies," said the association's president, H. Robert Wientzen, at the forum. "We think we need a very vigorous effort to root these people out."

To back up his claim, Mr. Wientzen said in an interview that the association was working what it called "Operation Silver Platter" to investigate significant fraudulent spam operations. The evidence will be delivered to law enforcement officials, who will be able to bring action without having to finance expensive investigations with government money.

But many at the forum argued that much of what e-mail users see as spam is sent by companies that include legitimate addresses and subjects.

"There is lots and lots of spam that has pristine headers," said Ken Schneider, the chief technical officer of Brightmail, a company that tries to block spam for corporations and e-mail providers.

To deal with that, Mr. Schumer, for example, proposes forcing all unsolicited commercial e-mail to include the term "ADV" at the beginning of the subject line. He also would order the trade commission to create a national registry of people who do not want to receive spam.

Congress and President Bush recently approved a similar national do-not-call list after various state registries proved to be a popular and effective way to cut down on dinner-time invitations for gold cards. The law takes effect July 1.

But Timothy J. Muris, the chairman of the F.T.C., suggested in an interview that he doubted such a registry would be effective for e-mail.

"If these people are already breaking the laws, what makes you believe that they will comply with do-not-spam lists," he said. The telemarketing lists did work, he said, because most calls were made by businesses that were otherwise legitimate and not committing fraud.

The idea of an ADV mark in e-mail subject lines has been a part of many state spam laws. There was a general agreement at the forum that so far this has not been effective.

The Direct Marketers Association and other mailers worried, moreover, that if such a rule were mandated users and Internet service providers would set their systems to automatically discard all mail with the ADV label.

"If we become emotional and irrational here, we are liable to throw the baby out with the bath water," Mr. Wientzen said.

But even if spammers do not comply with the law, argued Paula Selis, a senior counsel in the Washington State Attorney General's Office, prosecuting violators of straightforward consumer protection laws is much easier than proving fraud. The do-not-call list rules, for example, allowed the state to file for summary judgments against telemarketers who called people on the registries.

Ms. Selis and a number of other anti-spam activists argued in the forum that individuals need to be empowered to be able to sue companies that send them e-mail against their wishes.