In a data commons, data is pooled and shared as a common resource. This approach can address power imbalances by democratising access to and availability of data. Often, a data commons is accompanied by a high degree of community ownership and leadership and has a public good cause. Of all of the approaches mentioned in this study, data commons is the one with the most existing real world applications. As a term, it has been a seminal part of open internet discourse since the 90s. However, data commons can be created with very different rules and governance structures, not to mention different kinds of data. So, there is more than just one kind. Wikipedia and Wikidata are data commons and so is OpenStreetMap. In science communities, research data is often pooled to increase the impact of data held by individual contributors. Current discussions in literature around data commons revolve around building on the learnings of open access movements and applying them to new and more ambitious forms of data management. The approach is certainly useful for envisioning alternatives to power inequities that arise from corporate or state control of data in different contexts. A prerequisite is that they be stewarded responsibly, for which many refer to eight governing principles outlined in a seminal work by Elinor Ostrom from 1990. In practice, this could mean that a commons has conflict resolution mechanisms. Or that a commons ensures that the integrity of data is high or the confidentiality of data subjects is protected. Or that there be clear licensing rules to open or restrict access to knowledge or software code. It probably goes without saying, that technical tools and services (and often cloud computing) always form part of a digital data commons. When it comes to devising future data ecosystems that boost competition and enable innovation by diverse players, interoperability of such technical tools and datasets is an important consideration. Being able to apply data in more than one context, or by more than one entity, is part of an expansive vision for unlocking the power of collectively owned data by and for a community.
DECODE (Decentralised Citizen Owned Data Ecosystem) is a consortium of 15 European partners, including the cities of Barcelona and Amsterdam, who work to make more communal data available to innovators and civic groups to meet local needs. DECODE launched four pilot projects between 2017 and 2019 for privacy-preserving technologies (including distributed ledgers) to share data generated and gathered by citizens for communal use. One project was on participatory politics, another on environmental data, a third was on age/identity verification, and a fourth was an login system for hyperlocal networks (as an alternative to bypass Facebook). They see city governments as “custodians of digital rights”.