No matter how many users one talks to in designing a system, there will be a gulf between what a user wants and what a system can do. The belief that users even know what they want, or that somehow a library can correctly interpret the needs of users is at best presumptuous. To truly build systems that met the needs of users, we must let them build these systems directly. By transforming our library systems into participatory systems, not only do we better meet the needs of our patrons, we also build systems that reflect the core principles of librarianship ? getting away from simply adopting new technologies developed in other fields. This presentation will explore the concept of participatory systems, and talk about what from the Web 2.0 and Library 2.0 world is durable, and how to avoid the latest fads.