  Threshold concepts are key terms in domain-based knowledge acquisition. They
are regarded as building blocks of the conceptual development of domain
knowledge within particular learners. From a linguistic perspective, however,
threshold concepts are instances of specialized vocabularies, exhibiting
particular linguistic features. Threshold concepts are typically used in
specialized texts such as textbooks -- that is, within a formal learning
environment. However, they also occur in informal learning environments like
newspapers. In this article, a first approach is taken to combine both lines
into an overarching research program - that is, to provide a computational
linguistic assessment of different resources, including in particular online
resources, by means of threshold concepts. To this end, the distributive
profiles of 63 threshold concepts from business education (which have been
collected from threshold concept research) has been investigated in three kinds
of (German) resources, namely textbooks, newspapers, and Wikipedia. Wikipedia
is (one of) the largest and most widely used online resources. We looked at the
threshold concepts' frequency distribution, their compound distribution, and
their network structure within the three kind of resources. The two main
findings can be summarized as follows: Firstly, the three kinds of resources
can indeed be distinguished in terms of their threshold concepts' profiles.
Secondly, Wikipedia definitely appears to be a formal learning resource.
