Net-based collaborative learning discourses often suffer from deficiencies such as lack of coherence and coordination. It is suggested that the provision of two functionalities, referencing and typing, which learners may optionally use to ground their contributions during a chat-based discourse, can improve collaborative learning. In particular, we examined if goal focus, type of task and group size affect learning outcomes and the use of these functionalities. A chat-based system, called a learning protocol, implements these functionalities and serves as a net-based collaborative learning environment. Results suggest that a learning protocol is more beneficial for knowledge-acquisition tasks than for problem-solving tasks, and that the use of supporting functionalities increases when goal focus is on the group rather than on the individual. Also, there is a tendency that learning outcomes improve as group size increases. We propose that learning protocols provide potentially valuable design features that can promote net-based collaborative learning.