With the turn towards the digital age, a growing number of institutions in the GLAM (Galleries, Archives, Museums and Libraries) sector started to identify a need for digitising their different collections placing them online with goals to preserve and exhibit them in the digital environment. After the initial efforts to develop policies, methodologies and best practices in transferring the collections into the online environment, researchers and practitioners have started to investigate possibilities of communicating those digitised collections with the public and seizing the opportunities that arise from digitisation. One of the approaches that cultural heritage institutions started to explore in order to involve the general public in their activities on the Web is crowdsourcing - taking a job traditionally performed by a designated agent (usually an employee) and outsourcing it to an undefined community in the form of an open call. In the heritage sector this means inviting members of the public, (“the crowd”), to tag and classify, transcribe, organize, and otherwise add value to digital cultural heritage collection content. In this paper we provide an overview of approaches in using the collective intelligence in the cultural heritage domain. Key terms, concepts and corresponding case studies are discussed, providing the framework for crowdsourcing projects within the heritage sector.