This talk will focus on recent developments on the use of Big Data for urban planning, policy and business innovations. Examples of recent work in this area will be given. The importance of Open Data initiatives and open source tools and technologies will be discussed, as well as emerging informal networks of urban data infomediaries and civic hackers who are likely to play a transformative role in urban informatics. The value that citizens can bring through Information and Communications Technologies in cities of the future will be discussed with examples.