The Internet of Things (IoT) refers to the emerging technological infrastructure formed by everyday objects and environments endowed with computing and networking power in order to provide digitally enhanced services and responsive behaviors in the physical world. As with every technology, at the end points of the IoT, there are people designing and using this technology somehow. Designing interaction for the IoT presents old and new challenges. In this thesis, I address two of them, namely metacommunication and appropriation. The former has to do with the people who design the IoT; the latter, with those who use it. By applying Semiotic Engineering as a theoretical lens to the study of IoT technology, I conducted six studies using different research methods which results were combined in three contributions. Firstly, I am proposing a semiotic model of technology appropriation, which is proposed as an epistemic tool to support designers reflect on how users adopt IoT technology. Secondly, I am proposing a semiotic characterization of IoT technology as metacommunication called the semiotic engineering of multi-level and multi-sided technologies, as an initial framework for the application of Semiotic Engineering principles and methods to IoT technology. Thirdly, my research design was generalized into a macro-method for approaching innovative technologies research. I claim that it is an useful alternative in research domains where there is a lack of methodological and epistemological consensus and/or diversity, such as with new technologies. These contributions both extend the body of knowledge of semiotic engineering as a theory and provide powerful resources for designers and researchers to reflect on technology in a human-centered way, I argue.