I study how people collaborate to create content online. In my early work, I focused primarily on what people can learn through this process. The educational theory of constructionism advocates learning through working on personally meaningful projects. Can the Internet support constructionist, project-based learning? In my newer work, I also focus on the products of online collaboration as ends in themselves. Working together, people can create new kinds of products that were not previously possible. How do we support them in this creative process, and what new kinds of collaborations might be possible? How do interaction patterns shape the final product? How do software features shape interaction patterns? How does Wikipedia really work, and why do people contribute to it? These perspectives of process and product are mutually reinforcing--people return to create new content because doing so is fulfilling to them in some way.