What defines Web 2.0 is the fact that the material on it is generated by the users (consumers) rather than the producers of the system. Thus, those who operate on Web 2.0 can be called prosumers because they simultaneously produce what they consume such as the interaction on Facebook and the entries on Wikipedia.
Chapter 10, High-Tech Global Flows and Structures, p. 290 - Globalization - A Basic Text (2010)