The Internet of Things (IoT), a global Internet-based system of computing devices and machines, is one of the most significant trends in the information technology area. An accepted unified communication approach would be a prerequisite for its mass adoption. Semantic technologies (Semantic Web) have been advocated as enablers of unified communication. However, while there are particular advancements in research on application of Semantic Web in the IoT domain, the dynamic and complex nature of the IoT often requires case specific solutions hard to be applied widely. In the present survey, the semantic technology challenges in the IoT domain are amalgamated to provide background for further studies in the use of semantic technologies in the IoT.