In a sign of the difficulty facing federal lawmakers as they craft antispam legislation, Microsoft Chairman Bill Gates and Symantec CEO John Thompson have offered starkly different plans for combating the problem.

The plans were outlined in letters submitted by to the Senate Committee on Commerce, Science and Transportation.

The committee held hearings Wednesday to solicit input on the spam problem.

Writing to U.S. Senators John McCain and Fritz Hollings - the chairman and ranking Democrat of the committee, respectively - Gates said that spam, or unsolicited commercial e-mail, costs businesses billions of dollars each year and was eroding public trust in technology.

"(Spam) is decreasing our collective ability to realize technology's full potential," Gates wrote.

While trumpeting Microsoft's investment in antispam technology for its MSN online and Exchange and Outlook application customers, Gates downplayed the idea of a technological fix to the spam problem.

"There is no silver-bullet solution to the problem," Gates wrote.

Instead, Gates advocated for a multifaceted approach involving new legislation, increased enforcement of existing laws and a healthy dose of technology industry self-regulation.

The centerpiece of Gates' antispam plan was a proposal to establish global independent trust authorities that could certify legitimate e-mail solicitations, champion best practices and serve as a mediating body for customer disputes. Legitimate e-mail solicitation firms would receive a "seal" identifying them as a trusted sender.

Rather than creating a complicated new body of laws regarding spam, federal legislation should indemnify ISPs from blocking spam and pursuing spammers, while providing incentives for e-mail marketers to adopt best practices, Gates wrote.

For example, the federal government could set up a "safe harbor" program that would absolve online marketers that participate in self-regulatory organizations from complying with more onerous antispam laws, such as labelling spam e-mail messages with the "ADV" prefix, Gates suggested in his letter.

Symantec's Thompson took a different tack in his letter to the Committee.

While detailing the damage Symantec has suffered from fraudulent spam messages offering discounted versions of Symantec's software, Thompson's recipe for fighting spam shied away from proposing radical changes to current antispam measures.

The IDG News Service is a Network World affiliate.