..The emphasis on user-generated content, shared amongst online social networks, is typical of Web 2.0, the umbrella term for the current evolutionary stage of the world wide web. In this 'social web', swamps of data could be powerfully linked together. Search engines can trawl it to pick out whatever another user asks for. And user 'tagging', together with underlying machine-readable descriptions, means that related information can be easily linked. For example, clicking on a molecule could eventually bring up not just a 3D picture and a list of properties, but also the related online articles, experiments, videos and blog posts that refer to it..