The AddressingHistory project was funded as part of the Developing Community Content strand of the JISC Digitisation and e-Content Programme and led by EDINA National Data Centre2 at the University of Edinburgh,

This paper charts the development and delivery of a Web 2.0 informed community engagement tool and application programming interface (API) developed at EDINA in partnership with the National Library of Scotland, as part of the JISC Digitisation and e-Content Programme. The AddressingHistory Web tool enables members of the community, both within and beyond academia (particularly local history groups and genealogists), to enhance and combine data from digitized historical Scottish Post Office Directories with contemporaneous large-scale historical maps. The paper discusses the background of post office directories and the corresponding georeferenced old maps for Scotland, the technical platforms deployed including sustainable software components, and Web applications and services. It also examines issues relating to data parsing, user generated content (UGC) created by the community including georeferencing, and the use of social media amplification for community engagement and future directions. To conclude, the paper argues that to be successful online, crowdsourcing tools such as the one developed for this project require a critical mass of content to fully engage the user community and that such success will ultimately be measured by continual and extended use within the wider community.