Social tagging in contrast to the pre-defined categories and terms of a classification scheme, social tagging systems enable users to create and assign tags that meaningfully organize the content of a website. Aggregation of tags leads to the generation of a folksonomy, a socially-owned socially owned vocabulary, whose terms define and organize the content of a website from the perspective of members of the user community rather than that of experts. Open access is a set of principles and a range of practices through which research outputs are distributed online, free of cost, or other access barriers. With open access strictly defined, or libre open access, barriers to copying or reuse are also reduced or removed by applying an open license for copyright.