Starting from the Schumpeterian producer-driven understanding of innovation, followed by user-generated
solutions and understanding of collaborative forms of co-creation, scholars investigated the drivers and
the nature of interactions underpinning success in various ways. Innovation literature has gone a long way,
where open innovation has attracted researchers to investigate problems like compatibilities of external
resources, networks of innovation, or open source collaboration. Openness itself has gained various shades
in the different strands of literature. In this paper the author provides with an overview and a draft evaluation
of the different models of open innovation, illustrated with some empirical findings from various fields
drawn from the literature. She points to the relevance of transaction costs affecting viable forms of (open)
innovation strategies of firms, and the importance to define the locus of innovation for further analyses of
different firm and interaction level formations
