This comparative study investigates how two groups of design and technology students generated ideas in an asynchronous computer-mediated communication setting. The generated ideas were design ideas in the form of sketches. Each group comprised five students who were all 15 years of age. All the students were from the same secondary school but different classes. In this paper, the problem that led to the study is introduced, and its related topics from the literature review are elaborated in terms of the participation metaphor, online idea generation and scaffolding. With one of the groups supported by scaffold prompts and the other contrasting group not supported, the results showed that the two groups were active in their participation, but content analyses of the generated ideas in the transcripts showed that the group that was supported by scaffold prompts did not generate more divergent ideas than the contrasting group. However, evaluation of the generated ideas showed that there was more quality in the group of students who were supported by scaffold prompts. The findings are discussed and conclusions drawn to gain insights into how scaffold prompts could benefit student learning in terms of idea generation and how future studies in this area could be developed.