Abstract: From year 2006, thousands of students (aged between 5 and 18 years) and hundreds of teachers have taken part in PoliCultura, an initiative by HOC-LAB of Politecnico di Milano calling Italian schools to create multimedia “narratives”. A number of user studies show that relevant and substantial educational benefits are achieved thanks to this program. On the ground of the collected evidences, as well as of data from previous experiences with educational 3D-multiuser environments, this paper aims at raising a theoretical question: what is the role of the “Technical Knowledge” of the teachers in a successful technology-based learning experience? Does the TPCK model provide an adequate explanation? From our experience, Technical Knowledge, in fact, seems to play a different role with respect to Content or Pedagogy Knowledge.