After 12 years at CNET News, Jai Singh (left) is leaving the San Francisco internet news company and will be replaced by two people — Dan Farber (right), the new editor of CNET News.com, and Scott Ard (far right), who will head CNET Reviews. Farber had been editor in chief of CNET’s ZDNet, and Ard had been an executive editor in charge of CNET Reviews and News.com. Larry Dignan will take over Farber’s job at ZDNet, a business technology web site run by CNet.