Farnsworth House is a modern masterpiece of home design?a steel, concrete and glass single-story house in Plano, Ill., built in 1951. It\u2019s one of Ludwig Mies van der Rohe\u2019s best-known works, an icon of the International Style, studied at architecture schools the world over. And last December it was scheduled for auction, with no holds barred on what could happen to the structure.That\u2019s when, advocates say, tools of the Internet age?online communications, data mining and demographic software?made a real difference in their campaign to save Farnsworth House from an uncertain future. Historic preservation groups used websites and e-mail appeals to friends of architecture far and wide. That and media coverage prompted enough phone pledges to allow the preservationists to close the bidding at Sotheby\u2019s at $6.7 million. The National Trust for Historic Preservation plans to open the Farnsworth House as a museum this spring.Political organizing and fund-raising fixtures such as direct mail and phone banks aren\u2019t going away, but preservation groups are finding that new tools make them more effective. Websites and e-mail allow preservation groups to quickly assemble coalitions of politicians, developers and citizens to draw up and circulate plans, and repeat the process if needed, says Lisa DiChiera, advocacy director for the Chicago-based Landmarks Preservation Council of Illinois (www.landmarks.org)."Ten years ago, it was mass fax. Now mass e-mail lets us more quickly and efficiently get information to our members and to connect with other organizations that we see ourselves allied with, like environmental and smart growth groups," DiChiera says. "And our website is critical for background and updates."The Chicago group is a tiny band of eight compared with the Washington, D.C.-based National Trust. Its 300-member staff boasts more sophisticated fund-raising and lobbying operations. The Trust recently generated thousands of e-mails pressuring the Senate to reject a rollback of heritage protection requirements in federal road projects (which it did), says Dolores McDonagh, vice president of membership development. The Trust farms out the hosting of its complex membership software, but in-house it maintains a million-record database, accounting software, a network linking regional offices and historic sites, numerous websites and a BlackBerry server, McDonagh says. The Trust uses Capwiz demographic and organizing software to zero in on constituencies and tailor appeals, says assistant Web editor Meghann Sullivan.Online donations jumped from $29,000 in 2002 to $100,000 last year (out of $9 million total), says McDonagh. Online donors tend to be younger and more generous than the overall membership, she adds.Daniel Bluestone, director of the University of Virginia\u2019s historic preservation program, says that while e-mail and websites may increase communication, "preservation is about developing place attachments, and it\u2019s possible that the more we\u2019re in cyberspace the less we\u2019re living in real space."