Semistructured Messages are Surprisingly Useful for Computer-Supported Coordination

Thomas W. Malone, Kenneth R. Grant, Kum-Yew Lai, Ramana Rao, David Rosenblitt

1. Introduction

Trying to develop a system to support cooperative work (CSCW).

2. Semistructured messages

Definition - "Messages of identifiable types, with each type containing a known set of fields, but with some of the fields containing unstructured text or other information."

Example: seminar announcement (see figure 12.1/12.2 on pg 317)

Advantages of using semistructured messages:

  1. Allows computers to process wider range of information
    An automatic recognizer can key on the given fields, and doesn't have to try to perform plain-text recognition
  2. Allows communication of non-standard info in the unstructured fields
    This is the advantage over fully-structured communication.
  3. Reflects structure of the processing people already do in handling data
    That is, if the structuring is chosen correctly
  4. Provides templates for creating messages, making sure that all the necessary information is provided in the message
    This is the "checklist" effect: Rick, what paper is that and are we going to read it?
  5. Simplify the expansion and incremental adoption of systems
    It is easy to gradually add more and more structure to a previously unstructured system
  6. (Not mentioned explicitly in the paper, but comes up later)
    Allows incremental evolution of the system according to feedback from the users, by adding more structure based on user actions

3. Example: The Information Lens System

Basically, a souped-up mail system, with what would now be considered rudimentary mailing-list support. Also allows an odd form of broadcast via the 'Anyone' recipient.

4. Features Made Possible by Semistructured Messages

4.1 Automatic aids for constructing messages (see advantages 1 and 4, above)

These aids help the user to remember what to type, and are made possible by the presence of structure, which clues in the computer as to what the defaults or alternatives are.

4.2 Rules for Automatically Processing Messages

Private rules:
Extremely similar to systems like filter and procmail, which are based on the same notions of structure in regular email messages.

Central rules:
Rules for when to grab messages to 'Anyone'

4.3 Intelligent Suggestions for Responding to Messages

Allows default responses, including complex actions, to incoming messages.

The Info Lens system creates a sort of explicit implementation of bits of commitment networks (cf. Winograd88) - by including a full implementation of the path that a conversation takes, even more complex interaction would be possible.

5. Inheritance of Message Type Characteristics

Because the system is implemented in (Fruit) LOOPS, an object-oriented ersion of LISP, messages can inherit characteristics from their parent(s). This is useful because it makes implementation easier, and also allows the users to build a simple tree in their mind when thinking about message types.

6. Applications

6.1 Computer Conferencing
6.2 Calendar Management
6.3 Project Management and Task Tracking

This is similar to the uses systems based on these concepts, such as Lotus Notes, perform today.

7. Defining the Network of Message Types

7.1 Principles for Defining Message Types

Two approaches - the Hand of God approach, and allowing users to define their own types. It looks like the best approach is somewhere inbetween.

7.2 Message Type Editor - see Figure 12.7, pg 329

8. Conclusion