When they're creating new features, software designers talk in terms of "use cases." A use case describes steps that future customers might perform with a website. "Starting a group with friends," would be a use case for Facebook. "Buying a book" would be case for Amazon's designers.

China's announcement that personal computers sold from July 1 must carry Internet-filtering software pre-installed by the manufacturer should be a flashing red light to journalists and defenders of free expression online.


