The collaboration principle in multimedia learning, which consists of three related sub-principles, determines when and under what conditions collaboration will positively affect learning in a multimedia environment. Flashmeeting is an example of multimedia collaborative environment that allows for tasks of various complexities to be carried out (Principle 1) and stimulates groups cognitive processes (Principle 2) by providing tools for real-time group work (with synchronous sound, pictures, text, etc.), a repository for sharing documents, and even recording facilities for the meeting, making information available to all participants asynchronously after the meeting has taken place (Principle 3). Collaboration in multimedia learning is effective when the distribution of tasks is such that the cognitive processes involved in carrying out the tasks and the products of those processes are complementary and/or supplementary. The collaborative principles in multimedia learning rest for a large part on hypotheses and assumptions about cognitive load.