Whereas the management of scholarly texts and digital editions of primary sources remain the focus of the TEI guidelines, the comprehensive and flexible framework provided by the TEI has led some more — for the TEI — peripheral communities to take up the guidelines as their basis for the representation of their back-office content. One interesting example is probably scientific and technical information where the need of interoperability across several document types (standards, publications and patents) as well as document sources (authors or publishers) can be well accommodated using the TEI framework, under the condition that some additional mechanisms, but also occasionally a change in the underlying textual model, is operated within the guidelines. Using the domains of terminology and stand-off annotation as on-going I will exemplify the corresponding challenges and reflect upon on-going relevant implementations.