The second day of what should be China’s trial of the century opened at 8:40 a.m. on Friday with a tweet: “The presiding judge has called the court into session.” The source was the Jinan Intermediate People’s Court by way of its account on Sina Weibo, China’s most popular microblogging service, and the court’s 400,000 followers.

It shouldn’t have gone viral. But it did.

Within 10 minutes, this unremarkable post had been retweeted more than 2,000 times. Such numbers, and such speed, are usually reserved for tweets with a little more verbal panache, or celebrities posting selfies. So why the sudden interest in when a court convened?

The answer is supply and demand. Interest in the trial of Bo, a fallen Communist Party prince, is exceptionally high. But sources of news are limited. In fact, there’s only one: the Jinan Intermediate Court’s microblogging account. Purported transcripts of the trial, as well as procedural notices, are tweeted from there. There is no other live, much less original reporting on the trial. If anyone, reporter or otherwise, wants to know what’s happening in the courtroom, the court’s tweets are the only source of information (occasionally supplemented by brief video, with the proceedings muted, broadcast on state-owned television). Thus, those tweets tend to be retweeted extensively.

Bo Xilai’s trial was always going to be a social-media event in China (so long as it wasn’t censored). During his term as party secretary of Chongqing, Bo’s charisma and hunger for publicity earned him a reputation as a populist. Even after his fall -- precipitated by a murder committed by his wife -- Bo retained his populist credentials, in part due to longstanding multigenerational ties with some of China’s most prominent Communist families. At the same time, those ties mean that Bo would never be guaranteed a fair trial: His partisans would negotiate his verdict and sentence outside of a courtroom. Their decision, then, would be ratified in a courtroom, probably via a show trial.

However, during the 1 1/2-year run-up to Bo’s trial, there was considerable doubt as to how and whether the Communist Party would allow the proceedings to be covered by the media. The precedents for openness weren’t good: Last year’s trials of Bo’s wife and a police chief involved in the case were tightly controlled affairs, with photos and video released only after the fact. Indeed, if China’s leaders could operate without regard to public opinion, they likely would have held Bo’s trial in a concrete bunker and released only the verdict and sentence.

But those same leaders are working on a judicial reform package designed to placate a populace convinced that China’s courts guarantee justice only to the rich, the well-connected and Party members. Under such circumstances, Bo’s trial had to have the appearance of being fair and open as a means of assuring other Chinese that -- if the time ever came -- they too could have fair and open trials.

The problem in staging such an event would be persuading Bo to play along. He’s a stubborn showman, and if given the opportunity to testify in front of a Chinese public with whom he still enjoys reservoirs of support, he would likely turn in a stirring performance capable of embarrassing and undermining his prosecutors.

Some of the transcripts posted during the trial suggest that he’s been showboating, off-script, in the courtroom, anyway. For example, on Thursday he implied that he had been so badly mistreated that he confessed to things that he hadn’t done, while accusing witnesses of lying.

All of this information was tweeted within hours or minutes (nobody knows) of the testimony taking place. Yet, although there’s considerable interest in the trial from all quarters in China, other state-owned media outlets are restricted to reporting the trial as tweeted by the Jinan Intermediate Court.

Obviously, restricting information to tweets is an excellent means of control. With no television or newspaper reporters offering original reports, the trial can be portrayed the way the authorities want. If that depiction includes Bo calling his wife “insane,” as he did Friday, or implying he had been tortured, all the better: The proceedings look more legitimate. Better yet, because those statements occur on paper -- and not in videos that can be examined for facial expression or body language -- there’s limited opportunity to doubt their legitimacy.

Equally critical, the slow drip of information from a microblog lets the court build a public case against Bo without having to worry about its own coverage being scrutinized. Thus, late Friday afternoon the court tweeted unflattering transcripts claiming that the Bo family had traveled around the world courtesy of a billionaire benefactor, and had even enjoyed feasting on “rare” African animals. Collectively, these allegations are unlikely to endear Bo or his family to a Chinese public hostile to official privilege, especially when obtained by corrupt means.

But the more important reason for restricting reports to Weibo has to do with symbolism. For the better part of a half-decade, Sina Weibo and other Chinese microblogs have become important incubators of Chinese civil society, as well as hothouses for the expression of discontent with the Chinese government, the Communist Party and social ills. China’s propaganda authorities have made several efforts to corral this effort, with varying degrees of success. Microblogs -- and Sina Weibo, in particular -- retain a certain cache as forums where real-time transparency trumps the packaged news and commentary prepared for the masses by China’s state-owned media.

By transmitting news of Bo’s trial only via microblog, the court is, in effect, co-opting and perverting one of Sina Weibo’s most treasured characteristics: its ability to crowdsource real-time reporting that might otherwise be manipulated by China’s propaganda authorities. It is, in effect, a cynical and even contemptuous reminder that the Communist Party, jealous as ever of its monopoly on public opinion, won’t be loosening up any time soon.

(Adam Minter, the Shanghai correspondent for the World View blog, is writing “Junkyard Planet,” a book on the global recycling industry. The opinions expressed are his own.)

To contact the author of this article: Adam Minter at ShanghaiScrap@gmail.com.

To contact the editor responsible for this article: James Greiff at jgreiff@bloomberg.net