Weibo, a Chinese micro-blogging site that works as a substitute for Twitter, has made it easier for people to share information online. But the site is often the target of government censorship. Now, a journalism studies professor at Hong Kong University has developed Weiboscope - a programme that attempts to understand what people post online in China, as well as what gets censored and why. The programme is able to recover internet messages that have been deleted by China's censors. Stephanie Scawen reports from Hong Kong.