Duncan Hewitt investigates the impact of microblogging in China, where Sina's Weibo now has a greater membership than Twitter.
He meets the young people of Chengdu in Central China, who are part of a burgeoning graffiti, hiphop and dance scene.
Just 15 years ago there was no way they could communicate with fellow fans, never mind the outside world. Now they are breaking into the US charts.
He also visits Youku, China's YouTube, to watch their online X-Factor-style competition as it's filmed, and finds out why mums leading a breastfeeding revolution are addicted to their Sina Weibo accounts.
Thanks to microblogging China is also witnessing the emergence of a civil society of activists and justice-seekers. The victim of a horrific acid attack tells Duncan how her desperate plea for redress on Sina Weibo led to a nationwide outcry.
In Beijing he meets the dogs saved from a grisly death in the dog-eating South thanks to flashmob rescuers organised on Sina Weibo. None of this was possible before the internet - but where will it all lead?
(Image: A girl in a cafe using her phone)