Many people that would like to contribute at some level towards creating art in public spaces. However little is currently being done to make use of this untapped potential. The difficulties involved with collecting and coordinating dispersed talent often prevents it from being utilized. But now the Internet offers new opportunities to make harnessing latent talent much easier. Successful online platforms (such as Wikipedia and YouTube) demonstrate the potential value that can be derived from volunteers when appropriate systems are in place to utilize their contributions. Jeff Howe refers to this idea of harnessing distributed volunteered effort via the web as ‘crowdsourcing’. Which he explains as “the process by which the power of many can be leveraged to accomplish feats that were once the province of a specialized few” (2008). This thesis aims to investigate how an online platform might harness voluntary contributions in order to produce public art. The design objective for this project is to develop an online platform that allows people to contribute towards creating art in public spaces. My research explores the needs and motivations of potential contributors as well as techniques for harnessing voluntary contribution and coordinating group effort. As understanding human behaviour and user interaction is central to this project I have adopted a user-centered approach to research and development. To better understand the requirements of the proposed online platform user research was initially conducted in the form of focus groups with potential users and then via an in depth case study. In order to tackle the challenge of designing an entire platform the process was divided into distinct elements that could be addressed individually. These elements included the core functionality, the brand identity, the structural design, the interface design, and the visual design. For each element I consider what techniques might help to better harness voluntary contribution. The final result provides an online environment for people to get involved with specific art projects around their city. Projects are presented as separate challenges and users can contribute at many different levels such as sharing designs online, attending events, or simply providing feedback