The introduction of new online technologies in Higher Education brings many challenges for staff, not only in learning new functionality, but in deciding how to use tools in pedagogically effective ways. This case study describes an initiative at the Open University (UK), which set out to provide professional development in the use of an online synchronous tool. It focuses on the teaching potential in a number of different disciplines. The account describes the development of this resource, together with the perspectives of those engaged in producing it. We have illustrated a systematic approach to activity design inspired by threshold concepts and troublesome knowledge. We found that the demonstrators appreciated both the approach and the peer support available. The approach helped with identification of appropriate areas for intervention as well as in the design of activities and authentic use of tools. We suggest that the protocol adopted here is of great relevance to those adopting a blended approach, when deciding what tutor-student interventions should take place, and when. (Contains 1 table and 1 figure.)