"Internet participation-based media sites, applications" from "How companies can make the most of user-generated content", McKinsey Quarterly, August 2007. (Second Life contributions are defined as buying activity among total users).
Another graph of social content creation activity, this time from McKinsey and more number-specific. See the entire article (free reg) for more details.
- via Alexandra
Related:
Forrester Segments Social Computing Behaviors
Study: Content Creators Are Few
