The user's action is constrained by the interface. The left side of the chat area contains a list of links the user can take. The right side of the screen contains the chat form and all the possible actions a user can take while chatting. Figure 3 shows the top of a typical chat area. While engaging in chat, a user can either post a message, view new messages, clear the form, or configure their chat environment.
All possible actions are visible to the user.
Every action by the user results in a feedback action by the system. However, evaluating the current state of the system may be difficult at times. Because of net lag, a post may take longer than the user thinks it should, and at that moment, the status of the system is unknown. The user is left wondering if their post was accepted by the system or not. However, when the user reloads the page, they are presented with the current state of the system, making an evaluation of the system as easy as observing the information on the screen.