The interaction between people can be represented in a two-dimensional grid. One dimension of this interaction is space. Here we deal with the question: Where are people located while they are interacting? The other dimension is time. The participants can interact in a synchronous way, where they act at the same time, but they could also interact delayed in an asynchronous way. CSCW applications are therefore generally classified according to the two-dimensional space  that is shown in figure 1.1.
This is the field where interacting people are present at the same place and time. The most common examples are meetings and classrooms. Work groups usually hold frequent meetings in order to discuss, organize and evaluate topics. The CSCW tools used in this area are intended to replace the traditional blackboard. They reach from screens that project computer images onto a white screen to individual interconnected computers used by each person. In the later case, for example, every person has access to a virtual shared space that is seen and accessible by all members. Abstract material can be presented by a participant and feedback can be given in a way that is not possible with traditional blackboards. There is also the advantage, that external information, for example from the Internet, can be retrieved and brought into the discussion very easily.
This form of interaction was not present before humans learned to store information. Traditional examples are written words and drawings. For example, somebody leaves a note for somebody else is a form different-time/same-place interaction. A common example today is that people work at the same workplace in shifts. Those shift workers need to give instructions to the next shift. The computer can be used here to enhance existing administrative, filing, and filtering necessities . CSCW attempts to enhance time management as well as group information and assignment management.
Since computers are connected, they have been used by people who reside in geographically distributed locations to communicate and work together. Groupware systems usually provide shared workspaces, where users participate in form of virtual meetings. Such workspaces often implement the concept of WYSIWIS1.1. They can be further supported by audio/video teleconference systems, which allow the participants to hear and see each other.
The most well known Different-Time/Different-Place example is e-mail, which is by far the most used asynchronous form of groupware. E-mail is intended as communication media for two or small groups of users. Mailing lists and bulletin boards (newsgroups) are suitable for a large number of participants. The difference between mailing lists and newsgroups is that mailing lists deliver the messages to the user (usually via e-mail), while bulletin boards require the user to retrieve the information. Hypertext systems like the World Wide Web also belong to this field of CSCW. Other examples are group calendars and collaborative authoring systems.