But the real value of Twitter, he says, is what he learns by watching the other messages coming in — from college students, venture capitalists, journalists, and others he follows. "The fact that they're watching the news for me, scouting the Web for me, and editing the Web in real time — that's the value of it," he said. He started using the service more than a year ago after he was encouraged to do so by his friend, the journalism blogger Jeff Jarvis. Mr. Rosen says it complements his own blog, PressThink, letting him reach new audiences and interact with more people.