Semantic annotations enable services that make the knowledge in documents more accessible. In the case of ALeA, an adaptive learning assistant we use as a case study, they enable, for example, guided tours and practice problems tailored to the learner’s competencies. However, the cost of semantic authoring is substantial and tool support is limited. In this paper we discuss the nature of the semantic authoring task and argue that, while sharing aspects of both classical (informal) authoring and formal authoring, it is a task of its own that needs special editing support facilities. We present and evaluate a simple utility that supports the process of annotating technical terms with semantic references to a flexiformal content commons and increases annotation productivity by almost an order of magnitude.