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\u00a0Wednesday to solicit input on the spam problem.Writing to U.S. Senators John McCain and Fritz Hollings -\u00a0the 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.Instead, Thompson stuck to incremental and common-sense proposals such as increasing enforcement of existing fraud laws and beefing up the prosecutorial staff at the\u00a0Federal Trade Commission.Greater deployment of antispam filtering software by ISPs, better consumer education and a uniform federal antispam law to replace fragmented state laws would all help reduce spam, Thompson said.Neither Gates nor Thompson spoke in person at the hearing, where executives from America Online\u00a0and antispam company Brightmail joined representatives from the marketing and advertising industries and privacy advocates to voice their concerns about the spam problem and the various antispam proposals that are circulating on Capitol Hill.