The bulging prison population is a “scandal,” Rupert Murdoch declared this weekend, mostly due to “terrible state laws.” That is not only a surprising opinion from the notoriously conservative mogul, it’s on a topic that he would not usually tackle. The prison-industrial complex rarely comes up in Murdoch’s orchestrated interviews with “the press”—a term that is a stretch anyway, since he saves the best access for employees at his own publications, who have something of a conflict of interest while questioning their bosses’ boss. But Murdoch was not responding to an ordinary interview.

Murdoch was addressing an urge familiar to anyone who has ever wanted to correct something on the Internet, to respond to a question or accusation in the comment section, or to spar with a stranger even though you surely have better things to do. Murdoch was tweeting.

Specifically, he was taking up some of the thousands of questions and charges that have percolated on the micro-message service since he made himself available, sans spokesman, on the network. Even if you don’t like the man or the messenger, the 80-year-old’s scribbles on this six-year-old website are a reminder of how social networking still generates a remarkable amount of new interaction and information.

Murdoch’s prison post, like a good number of his 107 tweets to date, is reactive and even a touch defensive, as he dabbles in direct contact with critics (and fans) whom he would never otherwise hear from. The recent attention on tax rates in the US presidential race brought Twitter questions on Murdoch’s finances, which he gamely addressed last week: “Absolutely pay full income taxes plus NY state plus NY city!” That came after Murdoch had tweeted out against not only the discount tax rate for carried interest but against Wall Street itself. “Romney tax uses long-term legal loophole,” he typed, “‘carried interest’ makes all fund managers rich. Time both parties stopped selling out to Wall S.” One has the feeling he would have spelled out “street” if there were space. Ever the newspaperman, Murdoch is also solicitous towards the spelling police that live to correct digital typos. After his iPod made an erroneous autocorrection on a recent tweet, he thanked his followers for catching the error and added, “I should have checked. Sorry.”

While Twitter has revealed more of Murdoch’s mind, in real time, and given some random people a chance to reach him directly and elicit responses, you may wonder why a man who owns so many media platforms needs to opine on another one. But I don’t think anyone who uses Twitter would wonder. The service’s limits—140 characters for a message, no exceptions—are remarkably liberating. Responding to people in the open, lengthy framework of an e-mail can be daunting, never mind composing a memo or article. Twitter unhooks brevity from the stigma of rudeness. You can touch on something without getting into the weeds. You can acknowledge a question or criticism, genuinely, but avoid spending an afternoon on it. That’s not better than deep thinking and reaction, but it can be better than nothing, which is the alternative for many of the trending topics that percolate across the site.

In today’s Times, David Carr credits Murdoch for diving into the essence of the 2.0 experience. “Mr. Murdoch may not know much about computers, but he has an intuitive understanding of how Twitter is supposed to work,” Carr writes. “By mixing the personal and political, propaganda and plain old rants, he is serving his interests and the interests of his company.” Carr contrasts that approach to the hackneyed shilling of executives like Martha Stewart. She once confessed to Piers Morgan that she uses the site to broadcast her message and sell products, which makes her stream about as fun to read as a haiku infomercial. It is striking that Murdoch, who has been stubborn and wrong about many things in his long career, immediately grasped that there’s no point foisting more one-way communication on a two-way world.