The term open datarefersto freely available public and private data, that can be accessed, aggregated, and disseminated further by any citizen, provided that the user acknowledges the source of the data. Initially, open data offers were linked to data that was not private, confidential or classified as secret and was gathered, by public and private organisations, with public funds. The range of such data is very large, from weather, traffic, and scientific research, to statistics and election results. Freedom of Information Acts which have been enacted around the world opened public access to databases on public budgets and performance, on legal acts and on data gathered by public agencies on education, health, pollution or crime.
In addition, privately held organizations, like Trade Registers, offer access to lists of companies and their owners; stock exchanges store and make available free financial and business information on traded companies; privately owned companies share anonymised information online to help public organisations create better policies and plans of action. In the case of private companies, a commercial organization may decide to share online open data through a dedicated portal, such as Uber Movement, an Uber initiative to help urban planners. Data collaboratives are joined efforts by private companies, humanitarian organisations, and public sectors representatives to solve an issue, such as illegal fishing or an outburst of Ebola, based on available digital data.
Open data are valuable only if they can analysed and interpreted with relative ease and if the meta-data – author, publisher, timeliness – make the open data reliable. In the past, investigative journalists organized hackathons to gather programmers that are able to access public data on companies and make these data more easily searchable and readable. Today, there are public data portals available across Europe, and an European Data Portal that gathers not only datasets and data visualization portals, organised by categories and by country, but also lists of global re-users that make the data more accessible for the general public, through applications and platforms.
