Since Gibson's original idea of object affordances (See: WhatIsAffordance), software designers who create tools for communication and group interaction have come to speak of SocialAffordance. This expands the concept of designing affordances in physical environments to the development of software, and how it can afford certain types of interaction. Understanding social affordance, we can choose AppropriateMedia?.
The concept hierarchy might look like:
SpokeVsCircleCommunications talks specificly about the sort of social interactions wiki and blogs afford.
These both deal with synchronous environments (both based in conversation theory & gibson's concept), which I think is quite different, but good models because they are quite specific:
Define external redirect: AppropriateMedia