1. modern linguistics as a change of paradigms

Group Email List: Two-way, group, asynchronous

Direct messaging ("chat"): Two-way, user-to-user, synchronous

Video conference: Two-way, group, synchronous

Web Site: One-way, broadcast, asynchronous

When thinking about enabling communication in a software system, designers must consider when, how, and why users will need to communicate with each other. For certain situations text-based chat might be optimal while for others voice communication may be more efficient. Furthermore, for systems with many users, communication can quickly become noisy, making it hard for users to separate the important communications from the unimportant. Understanding the user’s goals and how they change over time is important for effective communication mechanisms. Communication almost always has context, and that context informs what the user is currently doing in the system.
The main challenges when designing communication within software systems are mapping communication to the appropriate context, providing the right communication mechanisms at the right time, and bringing important communication to the forefront at the right time.

Cooperation

When users are cooperating, they each have their own goals, but behave in such a way as to not interfere with each other. A good example might be two children independently coloring separate pictures, but with a shared box of crayons. Each child is primarily concerned with drawing her own picture and is not overly concerned with the picture drawn by the other child. However, the children agree to return crayons to the box when they are not actively drawing with them, so they will be available to the other child. Furthermore, if one child needs a particular crayon that is in use, that child can let the other child know he needs it, and the child using the desired color can return that crayon to the box.
In cooperative systems users may communicate more often in times where their individual goals overlap or when there is potential for conflict. They may communicate less often when their goals don’t overlap very much. Sometimes “rules of engagement” are established beforehand that define how cooperation will occur; other times cooperation happens in an ad hoc fashion. A key point is that when users are cooperating they don’t necessarily have to be aware of the other users’ goals / objectives. They only have to know how to behave in order to not interfere. In the drawing example, neither child needed to know what the other child was drawing. They only had to know how to behave with regard to the crayons.
If your users need to cooperate, the system should afford them a wide degree of flexibility in working independently, but also allow them to understand when cooperation with another user is required. When cooperation is required, the system must provide sufficient communication mechanisms or other indicators for all users to know how to work together without interfering.