In this paper, we discuss opportunities and challenges for technology development and adoption in public libraries. The results are based on a multi-site comparative study and thematic analysis of ethnographic work in three libraries, each in a different European country. The results explore the socio-technical practices, understandings, and perspectives of library staff and patrons when it comes to the role(s) and function(s) of libraries today. The contributions, which aim at informing the design and implementation of new digital services in public libraries, are twofold. Firstly, the main findings from the study is presented under six themes. Secondly, a list of key opportunities and challenges focusing on 1) media and technology literacy, 2) institutional transformation and technical infrastructures, 3) resource constraints among library staff, and 4) a shift in focus towards supporting activities.