The learning protocol approach implements cooperation scripts as automated discourse rules into a net-based learning environment. The purpose of learning protocols is to improve learning outcomes of distributed learning groups by imposing structure on the learning discourse. The main features of learning protocols are a referencing function, a typing function, and a predefined sequence of contributions. Previous work has shown that learning protocols can improve learning performance; however, it is still unclear which conditions are advantageous and which conditions are disadvantageous. We investigate experimentally a learning protocol with respect to two kinds of tasks, knowledge acquisition versus problem solving, and with respect to two motivational conditions, individual versus group incentives. Results indicate that learning protocols are more advantageous if the learning goal is knowledge acquisition as compared to problem solving; this effect is moderated by group size. Motivational conditions, however, do not influence learning performance.