From the identification of a ´deliberative turn´ in Science and Technology Studies (STS), it is possible to point out reflections in some innovation studies and practices. This article proposes two categories of public engagement: the first one, born in the STS, aims mostly at the technology producers, while the second centers the analysis on the innovation users. Although each category is divergent about its institutional settings and purposes, they are complementary conceptual frameworks that can be particularly useful in policy making for the development of Social Innovations or Technologies.