How Twitter differs from IM, email and Forums is important because new users always compare things to what they know. Obviously there is a sample bias, the sheer diversity and pure gems in the below replies tell us something about what's newOne way to define various tools (or ways to communicate) and how they differ from each other is to visually position them in various dimensions. For this purpose, I have developed a simple positioning model that I call "Positioning Model for Communication Tools". I have uploaded a first version of it to Slideshare.net and registered it under a Creative Commons Attribution-Noncommercial 3.0 Unported License.
In the presentation, I also attempt to position tools such as micro-blogs, e-mail, IM, SMS, blogs and forums. I would appreciate your feedback - such as what you think about the positioning model and how I have used it to positioned various communication tools.