In the leadup to the eagerly awaited arrival of President Obama in China, the government has gone to some lengths to avoid the Dalai Lama question coming to the fore – including an attempt to point to a history of slavery. (Last week, China’s foreign ministry spokesman implicitly warned Obama to avoid embracing the Dalai Lama by making reference to China’s claimed liberation of Tibetan slaves: “He is a black president, and he understands the slavery abolition movement and Lincoln’s major significance for that movement.”) But by focusing, to the point of paranoia, on forestalling any dissident upstaging, authorities may have overlooked a strategic question of greater immediate importance to the Obama administration: the Chinese blogosphere.

Obama’s reference to censorship and the internet in Shanghai today came as little surprise to those of us who attended a briefing last week organised by the US embassy. No traditional journalists were present; instead a range of prominent bloggers fresh from the fifth Chinese Blogger Conference in Guangdong province and a mix of opinion leaders were invited to three consulates in China, linked by a video conferencing system.

The respected blogger Wen Yunchao said many internet users wanted Obama to urge Chinese leaders to release the internet from heavy censorship. In response, Wang Zheng, from Chinese Media University, argued that mainstream public opinion was not bothered about internet freedom – that they cared instead about financial freedom and freedom to travel. Bloggers in attendance swiftly tweeted Wang’s remarks, triggering a big debate online. Within hours he had been given a new moniker by the twittersphere: Mr Mainstream.

And still Chinese authorities march to the same old beat. In recent days they have detained several dissidents and civic right activists, including Zhao Lianhai, Yao Lifa, Zhang Mingxuan and Liu Zhengyou. It’s the same mentality seen in the runup to the Olympic Games and after the Sichuan earthquake. The system is devoted to harmony in the short term, which leads to loss in the long term. But the booming internet cannot be controlled for much longer. It plays host to the panoply of opinions, collected in the form of a dynamic cloud, its shape constantly changing so that no one can map it.

Followers of Mr Mainstream, upon hearing Obama’s concerns about internet censorship, may respond by saying: “We are not censoring the internet, we are merely enforcing existing laws.” Maybe, but the internet has been anything but silent as Obama’s trip approached. Beyond the moderated discussion on the official Xinhua news agency website, thousands of voices have sprung up on Twitter, collected from the twittersphere in a tag called #obamacn, started by Rebecca Machinnon, a famous China Internet expert.

In his session with students in Shanghai – the only public meeting scheduled for his visit – Obama showed his shrewedness by sending a message about the internet and freedom of expression. One senses he knows something about the shape of clouds. It remains to be seen, however, whether the president will show the bandwidth in the next few days to make mention of the Chinese citizen and activist Feng Zhenghu, who has been barred from re-entering the country and remains stuck in Tokyo’s Narita airport, the very same airport through which Barack Obama passed on his way to China.