The degree of user participation in libraries is growing. Libraries open up to crowd-sourcing in two major ways: some time ago, user tagging was introduced into the library catalog, and now we offer patrons the chance to take part in collection development through patron-driven acquisitions. We move away from the institution deciding single-handedly what to buy, instead users have the possibility to create their collections in libraries. This suggests that they not only have the competence to search for and find material but also to participate in selecting and making it accessible. As the catalog shifts from a library inventory to a tool for accessing content (with an immense increase in data), so the user moves from a “consumer” of library collections to a partner in decision-making who has the skills to assess the quality of available information.