Recent research in Technology-Enhanced Learning (TEL) demonstrated several important benefits that semantic technologies can bring to the TEL domain. An underlying assumption for most of these research efforts is the existence of a domain ontology. The second unspoken assumption follows that educators will build domain ontologies for their courses. However, ontologies are hard to build, especially for not-tech-savvy users. Tools for ontology extraction from text aim to overcome this problem. We have conducted an empirical study with educators, both from Information Technology (IT) and non-IT domains, where they used current ontology extraction tools to build domain ontologies for their courses from their existing course material. Based on the obtained study results we have drawn conclusions about the existing ontology extraction tools and provided recommendations for their future development so that they can be beneficial for the TEL domain.