We’re all more conscious about our security on the web these days, but the power of search engines and social networks makes possible the aggregation of diverse sets of information to build up a complete picture of individuals. This can be of especial concern for children, who may not appreciate the risks. Using the web to market to, or communicate with, children and young adults can be a minefield, and is increasingly subject to legislation. Mark Wooding’s article ‘The Jigsaw Effect’ looks at some of the risks and the solutions.