This is a very concise little post that explains a lot of truth to the so-called Web 2.0 experience.
The Habits of Highly Effective Web 2.0 Sites [Dion Hinchcliffe's Web 2.0 Blog]:
"The variety and depth of the Web is such that not every Web 2.0 site will have tens of millions of users, nor should it. An effective Web 2.0 site is largely powered by its users, whose feedback and contributions, direct and indirect, make the site a living ecosystem that evolves from day to day, a mosaic as rich and varied as a sites users would like it to be. In other words, creating a high quality architectures of participation is becoming a strategic competitive advantage in many areas."