Ziff-Davis Inc. agreed to sell its 64% stake in the ZDTV interactive cable television channel to Paul Allen's Vulcan Ventures Inc., getting $204.8 million from its partner in the venture to help reduce debt. The computer magazine publisher, a unit of Japan's Softbank Corp., is selling assets to help boost its share price. The company hasn't made a profit since selling shares to the public in April 1998. The unprofitable ZDTV channel, launched in 1998, focuses on computing, technology and the Internet. Viewers can interact through its Web site and video mail and appear on air as part of the programming. New York-based Ziff-Davis rose $1.06 to close at $17.81 in heavy trading on the New York Stock Exchange.