Open knowledge (or free knowledge) is knowledge that one is free to use, reuse, and redistribute without legal, social or technological restriction. Open knowledge is a set of principles and methodologies related to the production and distribution of how knowledge works in an open manner. Knowledge is interpreted broadly to include data, content and general information.
The concept is related to open source and the Open Knowledge Definition is directly derived from the Open Source Definition. Open knowledge can be seen as being a superset of open data, open content and libre open access with the aim of highlighting the commonalities between these different groups.
Similarly to other 'open' concepts such as open data and open content, though the term is rather new, the concept is old. For example, one of the earliest printed texts of which we have record is a copy of the Buddhist Diamond sutra produced in China around 868 AD, and in it can be found the dedication: "for universal free distribution".
In the early twentieth century a debate about intellectual property rights developed within the German Social Democratic Party. A key contributor was Karl Kautsky who in 1902 devoted a section of a pamphlet to "Intellectual Production" which he distinguished from material production:
With the development of the public Internet from the early 1990s, it became far easier to copy and share information across the world. The phrase 'information wants to be free' became a rallying cry for people who wanted to create an internet without the commercial barriers that they felt inhibited creative expression in traditional material production.
Wikipedia was founded in 2001 with the ethos of providing information which could be edited and modified to improve its quality. The success of Wikipedia became instrumental in making open knowledge something that millions of people interacted with and contributed to.