In recent years, social computing technologies have emerged to support innovative new relationships between organisations and the public. Inspired by concepts such as collective intelligence, citizen science, citizen journalism and crowdsourcing, diverse types of organisations are aiming to increase engagement with the public, collect localised knowledge, or leverage human cognition and creativity. In supporting these approaches, organisations are often provoked to make their data and processes more open, and to be inclusive of differing motivations and perspectives from inside and outside the organisation. In doing so, they raise new questions for both designers and organisations. For example how are "official? and "unofficial? information sources combined or hosted, mediated, or considered reliable? Does the role of the professional change through greater involvement of amateurs? How are the motivations of members of the public harnessed for mutual benefit? This workshop brings together an interdisciplinary group of researchers to address those questions from different perspectives.