[shagie]

The question is "what type of interaction are you after?"

Chat systems are good for the "I need help now" and "I want to chat..." but for some things a single message takes an hour or day or more thought to formulate a proper response.

In those situations, the real time nature of chat causes discussions of a topic to become disjoint.

USENET, email, forums and the like can have single topic threads / chains / posts where one topic is followed across days or weeks or months which is sometimes needed for hard problems.