Participation inequality: encouraging more users to contribute - article by Jakob Nielsen

"In most online systems, 90% of users are lurkers who never contribute, 9% of users contribute a little, and 1% of users account for almost all the action. All large-scale, multi-user communities and online social networks that rely on users to contribute content or build services share one property: most users don't participate very much. Often, they simply lurk in the background."

Although partly a plug for a forthcoming conference, this typically confident article by Jakob Nielsen provides a well-grounded overview of the problem of participation inequality on the web, and makes suggestions as to what can be done to reduce it.