Users who are logged in to the system should be able to see other users who are online and logged in.
There should be a feature where users can chat with each other if they want to.
The chat system must support emotion icons, color text, user picture, option of change the background color and font.
It should be built in a way so new features could be added later easily. Some of the future features will be supporting voice chat (VoIP) and video communication.
When a user invoke messenger it should open in separate internet explorer window, which will not have any toolbar, address bar or menu bar unless they will be used only for messenger itself.